I'm trying very hard to avoid spoilers, so Tali returning is about the ONLY thing I know. (kinda hard to avoid that, she was plastered all over every site last week or so--plus it'd be very surprising if she WASN'T back, since she's a popular character and couldn't die)
For Bioware in particular, I like "not knowing" even basic companions etc. I bought KOTOR totally blind--didn't even know what it was, other than "SW RPG". That was my first Bioware game.
I'd heard about being able to change classes, but appearance? Hmmn. Only if they actually expand the choices/options to fiddle with---my Shep is as perfect as can be with what was available.