Ca c'est une bonne nouvelle!
"IGN: I have a soldier class character from Mass Effect, but now that I've seen this Adept video I'd like to switch classes. Is that possible at the start of Mass Effect 2?
Christina Norman: The feel of the classes in Mass Effect 2 is so improved from Mass Effect 1 that we didn't think it was fair to ask players to stick with the same class. While I'm sure you'd enjoy playing a soldier in ME2, I can totally understand you wanting to try out an adept, so yes you will have the option to change your class when you import. We have a story explanation for why your abilities may have changed as well, but I can't reveal that!"
http://uk.xbox360.ign.comom/articles/104/1049370p1.html
(c'est l'interview que urnot a posté plus haut.)
On peut garder le même perso de ME1, mais en changeant la classe.