I dont think Im spoiling anything because all was said in official interviews and what not, so... There were rumors that your Shepard may die at the end of the game. Regardless of that choice, Im guessing they might kill the character or make it appear for a short period of time in Mass Effect 3. You might get to play an alien in Mass Effect 3, who knows, eh?
I always wondered what female turians and krogans looked like, maybe they'll show some this time around. They at least explained the monogender asari in the first one =P