One thing that hasn't gotten a lot of coverage so far is the attachments. In Black Ops 2, Quick Draw, Sleight of Hand (its called Fast Mags in this game), Steady Aim (the laser sight), and Stalker (Adjustable Stock) are all weapon attachments.
I ****ing love that. I very rarely run a silencer in Black Ops 1 and there is no way in hell I'm going to to use a silencer over Fast Mags and the Adjustable Stock. I might even be tempted to use that 3 attachment perk in BO2.