One can iron out some critical minuses away with UI with SwipeManager0.0.3 and Organiser Feed.
Personally I have swipe down close, swipe left/right task switcher and swipe up application list. This way I always know where I'll end up when I swipe out from the program.
With Organiser Feed I have that pretty much useless screen in a use it'd been on my N900 and DesireZ anyway. I just wish you could add email, messages and phone launch icons on it.

I agree on many points and settings especially are a mess on N9. I disagree many usability things, such as call cancelling in the lockscreen; you might accidentally swipe it close when digging the ringing phone from your pockets.
Definitely agree on good points such as lousy lower left back icon which should've not existed at all in the first place, and adding more swipe to the application's UIs instead.

Portrait mode only seems to be the way in Android-land too nowadays, unless you use custom roms.