you might be right, but I'm afraid that gameplay and controls will be "downgraded", so that it will be easier to play with a 360 joypad...
It won't be, I say that with almost total certainty... There's no way they'd nuke Mouse and keyboard controls because it would just turn all PC Players off Live for good, and the scope of the system is gonna be limited enough to start with without them taking that risk.
....Then again, more bizzare business decisions have happened :S
I don't to a ton of online gaming, but I have done my fair share, mostly in MMOs, but I do have an Xbox Live subscription, done Gears, Chromehounds, and a few others. I can say that I really like what Microsoft has done with Xbox Live, it's not perfect, but I do like it. I'll tell you what I think is going to be the key point here when it's all said and done is the Gamer Score. Playing 360 games and getting those achievements is addictive and that's going to be a seller for Windows Live and Games for Windows. I don't know that I'll personally become a huge player in this market, but it's a nice touch I think. Plus from what I've heard Microsoft is enforcing some new guidelines for the Games for Windows branding so that devs can't just throw crap together, call it a game, and ship it. I've played Supreme Commander under Vista and my experience was noticably better under Vista than XP (dual booting my machine to a Vista partition). Titan Quest also runs a lot better under Vista than it does XP (even though it's not a Games for Windows title)...my point being it's about time that there were some better standards put into place for PC games. I can't remember how many games that I've played that I was unable to finish because of some issue that still wasn't fixed several patches in.
What will be interesting to see though is how the Keyboard/Mouse vs Controller debate starts hashing out. I've heard so much gripping and hype since the announcements for cross platform play, soon it'll be time to put up or shut up lol. I won't say anything because I'm decent on both sides and my preferences depend on the game. Shadowrun will be the begining test though. I've heard it's supposed to be balanced for both sides, but we'll see.