Really like the 10 point perk system it looks like they are bringing to Black Ops 2.
It looks like you get to pick 10 things that you want in your class.... Things like a primary weapon, attachments, grenades, perks, etc. So if you don't want a grenade or any attachments on your gun you get to choose two more things to add to your class.
They had a clip of a guy in the trailer who had NO PRIMARY WEAPON and had like 6 perks, a pistol, and three other perk looking things. Pretty cool idea.