Everybody seems to mean the window frame colour and a set of desktop background pictures when they're talking about Windows 7 themes. Does anybody remember what themes used to be in Windows XP? You could actually alter the appearance of the window frame, how close buttons and menu popups looked, put a texture on the taskbar, all those funny things. Microsoft themselves have published a number of XP themes over time (Luna on XP, Royal on MCE2005, Zune later on).
I don't say that most of those and the numerous third party XP themes were beautiful or even practical. But it was possible to create something nice. In Windows 7 (I suppress the existence of Windows Vista...) such a theme could well be used to increase readability to a level before Aero Glass again. I mean, you cannot really tell whether a Glass window is active or not. I've been tweaking the colours and transparency levels a lot recently but the only safe indicator is the close button: it's red when the window is active, it's colourless otherwise. Then there's the window title. It is always painted black, on however dark a background. Again, regardless of whether the window is active or not.
Turning off Aero is not an option in Windows 7 anymore. Classic design looks just ugly there. It already wasn't exactly looking good on XP with the wide start menu.
So, can we increase the readability of the Windows 7 UI with themes like in XP or didn't Microsoft learn a thing since the Windows 7 Preview "Vista"?