I realise that in Lion it takes a couple of extra steps but I keep seeing people say that the windows are stacked and that you can't easily select the one you want, when in fact you can.
4 finger swipe up to access mission control.
Select the top most window of the app you want (regardless if it's the actual window you want).
4 finger swipe down and all windows of that app type are arranged in a grid pattern with no overlapping and easy to see labels.
In fairness I've never used Snow Leopard in any meaningful way so I haven't had any exposure to spaces and expose. I just think that maybe mission control isn't as 'broken' as some people make it out to be.
Yeah its the addition of those extra steps that frustrate me. For example, if i have a bunch of visual references open in preview for a project i'm doing, and i quickly want to go to a specific image, in lion i have to:
1) invoke mission control
2) potentially swipe through all the desktops to find the one with the preview app
3) click the stack of pictures that represents preview to make it active
4) invoke app expose (the grid pattern of app windows you described)
5) visually select the image i am looking for
now my point is, since you are looking for a picture, nothing until step 4) in the previous set of steps will actually guarantee you a visual on the content you're looking for if its buried in a stack of app windows. essentially steps 1 through 3 do nothing more than give you a fancy zooming and swiping experience for finding an application. so unless you just enjoy pretending you're tom cruise in minority report, you might as well just:
1) press the preview app icon on the dock, this will INSTANTLY transport you to whatever desktop the app is located in, and make preview active and at the forefront.
2) invoke app expose
3) visually select the image
and now for the kicker, before lion, and why expose used to be SO awesome, when you wanted to find that open image:
1) invoke expose to see all your open windows in all your apps, with no overlapping
2) visually select the image
and the consequences of this inefficiency are endless. say for whatever reason you have some images open in preview and some open in photoshop and you want to find a particular one. unless you have pre-lion exposé which shows you all your images at the same time, it now becomes a guessing game in lion of which stack of app windows do i think its in.
consider another scenario where you are dragging and dropping files between windows. you want to move something from the desktop to a finder window you have open. you reveal the desktop, start dragging the file, invoke mission control, and discover that the window you want to drag the file into is buried in a pile again. now what??
my feeling is that the usage model lion (and assumedly ML) favours is doing mostly one thing at a time (like on an iPad/iPhone), and "multitasking" is simply task switching. if you just want to go from your Facebook page or blog post to iTunes, and you aren't in a hurry cuz you're hanging out at a coffee shop, it gives you some pretty animations while you're at it. and i love that on my iPhone; heck i'm even getting tempted by the iPad 3, not because it fulfills any pressing need, but because apple makes incredibly appealing casual computing experiences. and that is of value.
but i also come from the group of people who work in the content creation industry, and started using apple in the first place because they were at the forefront of innovation when it came to elegant tools for scatterbrained creatives who need to work with chaos. thats why i'm mourning these losses, not because what we're getting isn't decent in its own right, but because it is a shift away from the paradigms that first attracted what was at one time apple's primary target market. and i honestly don't see *anyone* moving to cater to that niche anymore.