From what I read in the GI magazine they seem to be revamping the game. Seems like they're gonna copy of CoD4 by leveling up and unlocking guns.
11 new guns.
Updated co-op where someone can jump into the campaign at anytime by controlling one of your squadmates.
13 new maps, smaller maps to make more instense fighting.
All the screenshots in the magazine still show you shooting from the hip instead of aiming down your sights like CoD2/3/4/Killzone2/etc
I think aiming down the sites is a must now days, it adds an extra element and realism to the game. Aiming down sights = more accurate shoots, shooting at hip = less accurate. But I guess they're not gonna do that.