The old Exposè had one basic design concept, that entirely backed its usability principle:
It showed all open Windows in their relative size and moved them in place in a smooth motion, so the eye of the user still got track of which window is which.
The point is that windows you see are not lost. The number one reason why people use Exposé is to find a window they have lost. The second one is getting on overview. Before Snow Leopard both things were something Exposé did really really badly. Windows that were hidden behind another view is something that you can resolve by using Exposé. In this case it really has no use whatsoever to track it visually (it's hidden so that already makes it impossible).
Exposé is about finding the content you were working on, not about seeing where windows on your screen went. Try tracking 20 windows on a 13" screen when using Exposé in Leopard and even Tiger. That's just completely useless since due to the small screen all windows are stacked behind each other. Positions on the screen are nearly the same so that does not help you in finding the window. Those 20 windows got scaled down so Exposé showed the maximum amount of windows (no, Exposé does not always show all windows, it is limited in that due to the screen size) making those windows tiny and thus impossible to identify (they all looked nearly the same). In other words: the basic concept of Exposé as you define it fails miserably on such screens and that is because the size of the screen plus resolution are the limitations in this case. Due to those limitations a visual way of tracking your windows is quite useless. It only works on big screens with high resolutions.
In case of the small screen example you really had to go check those open windows one by one by either hoovering over them so you could see the label (or use the option key) or use the tab key. A better way of doing it was using show all application windows aka F10.
Other things Exposé couldn't do was sort by application, find as you type (type the name of the label and it will be highlighted) and show minimised windows. The last one is a big improvement because that fixes the situation where the user has minimised a window, forgot about it and is now looking for it.
The new Exposè snaps into a lined up homogene grid view, leaving out every clue for better recognisation after being invoked.
The sole concept of existence of Exposè has been nuked.
The sole concept of Exposé was nuked in previous OS X versions but has now finally been fixed. Visual recognition is very unreliable, especially on laptops with small screens and lot of windows. However, the grid view does need some improvement, the spacing is quite large and should be a bit smaller. The scaling problem only exists when there is not enough screen to display all the windows. The grid has invisible boxes in which it puts the windows. The size of those boxes are limited. That's why the scaling is awkward when you have a lot of windows and a too small screen. It's a compromise: you can now display more windows when using Exposé but the window sizes are really awkward. They could have done it the old way but then you have windows with sensible sizes and a very broken Exposé since it is now unable to display a lot of windows. If you're looking for a window (which is the sole purpose of Exposé) you have to have some luck: the window you're looking for has to be among the displayed windows.
-it shows a "focus" (blue glow), that is not needed at all - I know, which Window, I am working with!
And that is absolutely the most dumbest thing I've ever heard/read. It is not about the window you're working with, it's about the window you've selected!
The blue colour is for highlighting a window. It's about showing the user which window has been highlighted. It's a visual reference so the user has a confirmation that whatever he wants highlighted is actually highlighted. It is also used in various other parts of the OS, applications and even things as websites (pulldown menus and such).
-it shows minimised windows (I minimised them, because I do not want to see them in the first place!)
It shows them because if you're looking for a window it might well be one of those minimised windows. It is especially useful when you have enabled the option to minimise windows to the corresponding dock icon. In that case there is no other way of knowing you have windows minimised.
-it unifies size of all windows, resulting in unreadability of fonts and a much harder identification
Exposé has always done that: make things unreadable and really hard to find. It did that when I used 10.4 and it still did when I used 10.5. Unfortunately I was stuck with that, there was no alternative. In 10.6 I'm still stuck with it but Apple finally gave me an alternative as I can now search the labels and use Dock Exposé (cmd-click on other dock icons is really nice, custom made Exposé). I can now actually find windows so no need to hide apps any more.
I think apple needs to give me the option to do what I want. It's a matter of preference I think. The OS should adapt to the user, not the other way around.
That would be ideal and also instant hell. If you have a lot of options people will get lost. Linux has the thing you want (it adapts to the user). Unfortunately it is also the number one reason why it fails: users hate the enormous choice they have. They just want to get one with it and not waste their time by having to go through all of those options. The problem is you can not satisfy every user which makes an OS that adapts to the user impossible. A very good example at what different users want is the continuing flamewar between KDE and GNOME.
But you're right, it really is a matter of preference and has a lot to do with the way people work. The main thing is that Exposé was always meant as a tool to let users find the windows they want: it's all about window management. OS X itself is a very windows based OS unlike Windows and windowmanagers like GNOME and KDE. Some people use Exposé differently, they tend to use it as a visual references to what window is where and they know what is inside a window and/or what it represents. That is quite differently from what Exposé is actually for. Maybe in this case just the option "use old Exposé" will be enough.