What you say about Win7 is true in my experience, except for the "slick" part. It's functional, but it's not slick, software-wise. It's NT6.1. Microsoft is gonna have to throw out the ancient, creaky NT codebase before they can write something that I'd call "slick" from a technical point of view.
On the other hand, it is glitzy, I'll grant that. But that's the first thing I turn off when I set up a Win7 system -- I get rid of all that glitzy crap, because I use Windows to do work, not wank over some damn translucent windows.
I did find one app that doesn't run on Win7-64, but I'm pretty sure it's the app's fault. I've contacted the vendor to see what they're doing about it. So far there are a number of older app installers that won't install on Win7-64. That's not too surprising.
Overall, great OS.
I gotta ask you, though. Do you write marketing copy for Microsoft? I'm not saying you're a MSFT shill -- I'm just saying you sound like one sometimes. :)
I must say a lot of the slick you may or may not like is quite functional as well. Aero-peek, alt-tab,dragging the windows to the side for side by side viewing and other neat features are fantastic. When I am writing a report for some bacteria I am investigating it is great to have my notes on one side and word on the other. If I have something pinned on the background such as a calender or clock, or even a newsfeed it is great to just go down to aero peek and take a quick look.