One "feature" that raises the most questions is the Dock. The "dock" is borrowed from NeXT (with some improvements).
People mistakenly credit Windows with innovating this behavior (with its taskbar) -- but NeXT had something similar years earlier, and I'm sure some individual applications and GUI's had it even earlier than that. I remember the Lisa used icons and applications (with it's 7/7 suite of Apps) on the desktop in a not too dissimilar behavior, and I seem to remember other earlier partial examples as well.
Good behavior -- A place to minimize
The dock is an easy behavior, at some level, for users to understand. It is basically a place for running applications (files) to go (a row of icons across the bottom of the screen) -- in order to make changing state between these applications easier. Each application you run, gets automatically added to the dock (a row along the bottom of the screen). Every icon you click from the dock, brings that file (window) to the foreground so you can work on it -- and each time you click minimize on a window, it returns to the dock. And apple did a spectacular job of clear transitions (animations) to explain what is going on (the genie effect).
The Mac has the Application menu, which is a tear-off menu/palette/dock of its own. It also allows users to hide applications, and still have a way to bring them back. The advantage of the Macs Application menu is that it is not normally taking up screen real-estate -- to see what is running you must select the menu. This is great for space savings -- but new users can easily forget what is running because it is not staring them in the face -- so the advantage is also a disadvantage. You can tear off the menu to become a sort of dock, but that is not the default behavior so newbies can get lost (I've had to explain the Application menu more than a few times to new users). The dock is an attempt to improve all that.
The biggest advantage of the new dock is that you have a place for minimized windows to go. On the Mac minimized windows (WindowShade) just leave their title bar where it is and hide the rest of the window -- which has always been an ugly behavior. With Aqua they reduce themselves to an icon and get out of the way. Users can see what is running, and manage windows a bit better. Another nice thing is this behavior is borrowed from NeXT, and so NeXT users will have some features that will keep things familiar for them as well -- and there are improvements to the way this dock works over the way the old NeXT dock used to work, so things are improving for them as well. So I like what the dock is trying to do. Unfortunately, it tries to do too much (for now) and so it sort of falls apart.
Now while I do like the idea of having a dock -- and do like some of the behaviors of the Aqua-dock, there is a lot of bad in the first implementation as well (or some behaviors I do not like, or think could be better). I fully expect that things will change and improve before release of OS X -- but as a preemptive strike, here are the few things that I definitely think need improving.
Icons alone - the Mac interface used icons, but the Mac understood the first rule of icons -- "Icons are not enough by themselves!" The Mac had icons to help explain what something was, but it always had text associated with the icons for those of us who could read. The icons helped clarify something and offer more information (like file type, or what it did) -- but was not the only information about something that was displayed. NeXT, sherlock, and now the dock have this thing with using icons alone to differentiate something -- when the image by itself is just not enough. What if you dock 12 folders or TextEdit documents? They all have the exact same icon so how do you differentiate them? At the least the dock will have the little "tips" that popup when you move over the icons -- but even then I should haven't to play hide and go seek (with the mouse and icons + text) to find out which icon is the one I want.
Relocating the dock - I'm hoping that you can move the dock from running across the bottom of the screen, to running along a side of the screen. Vertical screen real-estate is more valuable than horizontal real-estate. This has to do with reading long pages of text, and screens being wider than they are tall, and it isn't always true -- just usually true. So I'd much rather have a vertical dock than a horizontal one, or at least a movable one -- but we'll have to wait and see on whether it is movable or not.
Autohiding dock - I really don't like the automatically hiding docks if it works at all like Windows. Steve Jobs alluded that the dock would have that option. The problem is that the edges of the screen are boundaries that pin things in. When the user moves the mouse towards to the bottom of the screen (say to select the horizontal scrollbar or grow box on the window) they are highly likely to overshoot and hit the bottom of the screen -- at which point the autohiding dock leaps up and blocks the scrollbar and growbox, thus obstructing your work. You must move the mouse up quite a bit (to get the dock to go away) then come back down very slowly to make sure that the stupid jack-in-the-box interface doesn't leap out to annoy you. This is bad interface -- and how Windows taskbar works. It is also bad interface because it is hidden. A far better interface is something like the control strip on the Mac or popup windows -- which leaves a little tab on the screen to offer a visual cue that something as there -- and you must discretely click on it to bring it out (or hide) -- thus eliminating surprises. So I'm concerned that Apple do this behavior correctly.
What the hell is it for? The biggest issue I have with the dock is the ambiguous and unclear behavior of what it is for.
If the dock is to show state for running applications, that is great -- then each Application will be docked. But sometimes users want files (documents / windows) to be docked so that that they can switch among multiple documents (whose icons all look alike). So then what happens when you have no documents for an application open, but still have the application running? Is there an Application icon as well as a file icon?
On the current Mac interface, the Application menu is for switching Applications and the window-shade behavior is for hiding and showing documents/windows -- the Dock is trying to combine both into one interface, and that makes it more ambiguous and confusing (and more like Windows). So the "is it a document or an application dock" question needs to be answered -- and it should be one or the other and not try to be both. Or at least if the dock tries to do both, there needs to be a way to organize it so that an applications documents stay near the application or somehow demonstrate the relationship between them.
But then we come to another bigger question -- is the dock for showing the state of running applications or a place to dock applications that you want to run. Steve Jobs showed both. So sometimes he was dropping aliases (pointers to files or folders) into the dock -- as a place to put them and make it easier to run things. And it is easy to run things from a dock and train new users. However, icons were also automatically added to when you ran something else -- meaning that that the dock was then being used to show the state of running applications and files. The dock was also reordering things based on new things that were run so that you couldn't predict where anything would be placed in the dock. And what the hell is the trashcan (or wire pencil holder as it now looks like) doing in the dock? How does that add clarity and improve the interface? Dragging things to the dock are to open and run things -- not delete them. They lost the whole desktop metaphor with that one. What a mess. One behavior per dock please.
Running a new file/application takes a lot more time than just switching to a running app -- so those behaviors probably need to be differentiated. I would much rather that there were two different docks say one across the left hand side of the screen to show what Applications or files that you could run, and another along the right hand side of the screen that showed which were running -- in order to keep these behaviors different. Or one dock (at the right of the screen) that starts with the top icon and works down (for running apps), and another dock that starts at the bottom of the screen and works up (for docked apps). Or maybe even two different control-strip like docks for he different behaviors. Or at least have some coloration, sort order, or other difference between the icons to differentiate the different behaviors. Or they need to go back to two totally different controls mechanisms like on the Mac. And I like a dock -- for one thing or the other -- just not for both.
What about Popup Windows?
So in general, I like the dock as a behavior for switching among running documents -- and dislike it as a place for docking applications or files that you might want to run -- or there needs to be a separate dock for that behavior. What is more annoying about using the dock for storing "future" application is that the Mac interface currently has a better behavior for docking and organizing applications that you want to run -- those are popup windows.
On the Mac you can drag any window to the bottom of the screen, and it becomes a docked window (a tab).
When you click on the tab, the window will popup and show the list of icons (documents or applications) that you wish to run. This allows power users to arrange their docked applications by topic. Also the dock has a limited size, and therefor a limited number of things that can be docked -- popup windows allow for far, far more choices. I have ten to twelve popup windows, each with up to fifty icons. The Aquadock can't hold five hundred icons, and isn't arranging them logically/topically, and it also can take up more places (icons) because it has to show both running applications and documents and docked ones.
Copland expanded this interface idea even further. You could create a docked (popup folder) that would automatically search for all Applications in the system -- so that when you opened that folder, it would have any app that you added to your system (automatically). You could also do that for any search criteria -- like files that you worked on today, or files that had been tagged, and so on. Anything you could search for, you could save as a smart folder, and you could dock a smart folder (as a smart dock). This was a far richer behavior -- and with the Aquadock I think we are going backwards in functionality. The dynamic searching of Copland was far richer than Sherlock or what I'm seeing come out of Apple 5 years later. I'm glad NIH (Not-Invented Here) syndrome is over -- but lets not ignore great ideas that were invented here.
What about the Dekstop?
The single biggest concern by Macintosh users, and the one that non Mac users don't seem to understand (Steve Jobs included), is the Desktop. The whole Mac is built around a "desktop" metaphor. Files look like pieces of paper, folders look like a folder (and they contain things), and before you've properly arranged things, they just go in this big pile of messy stuff on your "desktop". The metaphor behaves just like life. As you work, you slowly clean up your desktop (do things, throw them away, and file them), until some other crisis clutters it up again. This is how many people work -- gather crap you need to do work -- then arrange and file the crap. The desktop is the workplace and buffer to collect things, usually around some common theme, in order to get that task done.
There are many technical reasons why it was hard for Microsoft and NeXT to properly implement a desktop. Basically it requires a large amount of programming effort to do one right, and companies are inherently lazy. But it is something Apple was able to do in 1984, and I have to believe that if it was a priority, that Apple could easily implement on OS X as well. Instead Aqua will have the NeXT, (other UNIX based UI's) and Windows-like solution that I call the NeXTOP.
The difference between a NeXTOP and a Desktop, is that in a NeXTOP you can't put files or folder on the desktop and use that screen space (and virtual space) as a big buffer. At best the NeXTOP is a place to put aliases (shortcuts) to files and folders which are contained elsewhere. So the NeXTOP is not really a desktop at all -- instead it is nothing but an extension of the dock. since it only points to things that are elsewhere but doesn't contain anything on it's own.
This NeXTOP behavior is close to a desktop, so close that many users (who haven't used a desktop) don't know the difference -- but is not quite the same thing. To those who are experienced Mac users it is an annoying (and incomplete) half-solution. To Mac users, they keep wondering why they can't drag a disk, printer, folder, or file to do operations on it -- instead they have to first "find the original" item (not the shortcut) then do the operation there. More than that, the desktop reflects things -- a disk is plugged in (or a CD is put in a drive), it pops up on the desktop. This is important feedback, and an active interface that makes the whole metaphor work. I doesn't work with aliases, and I don't want to tunnel in a level or two and double click things to SEE if something happened. There are logical reasons for having the desktop just represent what is connected to the computer, and not having to dive into an extra layer or two of hierarchy to figure it out. For the last 15 years, the Mac way has just worked better.
Now there are some negatives with the desktop as well as positives. Allowing people to pool their garbage, makes for a big potential clutter heap. Many people are bad at arrangement, and so their virtual desktop looks like a teenagers bedroom. Over the years I've seen hundreds of cluttered and disorganized desktops, and confused users because of that clutter. With the NeXTOP you can't do this bad stuff (as easily), and you must file things as you go - so things usually stay much cleaner and more organized. For new users this requires a little more training, but teaches them discipline (and forces it on them) from the start. And because things can't be misarranged as easily, it actually saves new users time because they don't misplace things (as much). However, while this forced discipline certainly helps keep things less cluttered, I'm not sure it is the right way to do things. The point of the Mac is that it is the users computer, and they should have the right (and power) to clutter things up if they want to. The way I work is that I constantly download 4 or 5 things on a topic (to the desktop) then file them (en mass). I temporarily put things on the desktop that help me get a task done. I can also have other things (popup windows, the real disks or folders) that help me arrange things. I'm very good at it, and doing this quick collect and then arrange method is faster than having to arrange each and every thing as you go. So the new interface (Aqua) goes out of its way to make me adapt to the computer -- instead of the computer going out of it's way to adapt to me. This change in interface philosophy is not progress.
So the NeXTOP is a worse metaphor and is a step backwards for Mac users since it basically means that things must be arranged the way the computer wants them to (to some extent) and not how the user wants to. It is as "user friendly" as having some desk-nazi standing over your shoulder, and screaming "NO!" every time you placed something on the desk instead of placing it in a proper "folder". Gads, this brings me kicking and screaming back to my childhood when I would use one of my dads tools. Sure, it teaches discipline and helps teach me how to do things that the computer (or desk-nazi) wants -- but it isn't a friendly computer doing what I ask it. I can't think of this as a step forward in interface. It isn't the Mac way. All the screen real-estate of the desktop is wasted potential (and can't be used as easily) -- though because windows were often opened up over most of this area, it isn't a huge loss.
Now with all those "negatives" about the new desktop being said, and they need to be said, the reality is that I'm not sure it matters. Most users aren't power users, and most users will quickly adapt to the slightly more "forced" philosophy of the NeXTOP. Once you are one or two levels into the file hierarchy, things behave basically the same. So it adds a step or two -- the earth isn't going to end over it. And it isn't torturesome -- in fact, once you use it for a week or two, you will become trained and just work with it. Mac power-users will bitch and scream at the interface change -- and the only reason there isn't more being said now is that most Mac reviewers are failing to notice the loss, and most Mac users haven't yet got to work with Aqua to notice the behavior differences yet. I will agree with their complaints, to a point, but there are tradeoffs. Overall we Mac users will adapt if we have to, and it isn't the worst thing Apple has done -- it probably isn't the worst thing they've done this week -- but I still hope we don't have to adapt to it, and that instead the computer will again adapt to us.
Even if we are forced to use the NeXTOP, maybe some enterprising third party developers will improve the interface and give us a real desktop (if Apple doesn't). Maybe Apple is planning on surprising us by doing so on their own real desktop (and not the NeXTOP that we've been seeing for the last 3 years). Personally, I've used both -- and while I'll morn the loss of my good friend (the Desktop), and I'm saddened by the interface taking a giant step sideways (if not backwards) -- but I will get over it, and go on. I find that the NeXTOP is completely usable on its own, and easy enough to train new users on (arguably easier, since they file things better) -- and if I hadn't have been spoiled by the Mac way it wouldn't be a big deal at all.
So the dock as a place to store applications that "might" be run, is fine for newbies. It is clear and easy to explain and use. But for power users it is limiting. Normally they just wouldn't use that function -- and they will be happy as long as they still have their popup windows (or some similar behavior). However, if you take away popup windows, and try to cram the inferior dock as the only way to solve that problem, there are going to be some unhappy power users. And while power users are a small minority of users -- they are a very vocal minority. (So you will hear a lot of noise).
There are also still a lot of questions and details that I don't know about the dock yet -- and I don't like ambiguous and multifunction things -- far better to do one thing well than three things poorly. The dock is easy to use for newbies (in some ways), and it is a far better way to allow minimizing of windows than the current Mac way -- but is a huge step backwards for power users. And unless it is more clearly defined (what it is for) then the ambiguity of the interface will far outweigh any advantages (in visuality) that it might have offered. And Apple needs to make sure that we gain functionality as well as usability -- in this area, wiht what we've seen so far -- we are gaining a few things, and losing many others. I'm hoping what we've seen isn't the full feature set.
I certainly don't think we've seen all the features in Aqua. Steve Jobs is sharp enough that he showed us just enough to make our mouths water... and I don't think all the Mac users should get pissed off and start the usual religious jihad's about our favorite missing features just yet. We are getting quite a few steps forward, and only a few steps sideways or backwards -- so lets not lose that perspective. It is possible to have a dock and some sort of popup windows, and Apple might even get a clue and add a real desktop -- so it is obvious we should give Apple time to evolve things before we break out the pitchforks and torches. But I do think constructive feedback, and raising concerns is acceptable, as long as we don't forget that things are a work in-progress, and we don't lose perspective about the whole suite of features we are getting, and get lost on one or two details that we do or don't like.