Got some replies from JP and via bugzilla.
#1: Until now I've got the display driver via YOU. So this has changed. Anyway it works now.
#3: I am not sure about ssk-askpass. I've not put it into my gnome-session again, but its not taken effect anymore. It does come up, I enter the password, but the key isn't keps (ssh-add -L does not show it). Seems that the way those processes are spawned has changed.
#4: sorted out via #191189.
#5: magically disappeared.
Still some problems with sound, but I won't complain about that, as I have rather unusual audio-cards. Also some packages had troubled with installation from the net - will try again later. This beagle thingie is a bit disturbing. In 10.0 it was eating all my memory, so I disabled it. Now it spins my hard-disk since at least an hour ...

Of couse it doesn't work at the first try. But the outcome is this 