Hey you both, thanks for your answers!
First: No, the WP7 KB of course is not that bad (I overplayed it a bit intentionally). But anyway I have to claim that I can still type much faster with an 12 button layout KB due to the fact you can type yours words absolutely blind (I´m sure you also remember these days where you were making a coffe with your left hand, ignoring that your right hand is typing something into your 1 m³ Nokia brick?!). The qwertz/qwerty layout is a good thing, but for me it´s still too small to type something in without looking at it.
Second: Since every mobile OS offers you a bunch of different keyboards (qwerty/qwertz; 12 Button; swype; etc) and every keyboard has it´s own fan community, I think it´s not that an absurd idea, to want this "freedom" on an WP7 too, is it?
Third: Yes, I do have a HD2 with an *goddamned, look at this very* big screen. But: The screen still has issues (eg ghost movements), what makes it sometimes difficult to get accurate results even when you make an effort to exactly hit the button...of course, this point has nothing to do with WP7 itself.