You missed out.

2~3 Shot kill out to 2x the range of a AR, decent if not faster ROF than a AR, and more stability via the Grip attachment.

Actually yes there is a limit since each gun has to be loaded in to memory each time the map loads and on consoles that is a limited amount. Each gun graphic takes up a set amount of memeory and is loaded every time the map is loaded even if a no players are using them or not. It is not just the simple coding of how they work that is loaded when a player picks a gun up or changes loadouts. Everything about that gun and all other guns is preloaded in to the memory at the start of each match.

Well, if they're going to put in the AK74u, here's two things:
1.)  NAME IT "AKS-74u", BECAUSE THAT'S THE GUN'S ACTUAL NAME.
2.)  MAKE IT AN ASSAULT-RIFLE, BECAUSE THAT'S WHAT IT ACTUALLY IS.

As for a possible new gun never seen in a COD game, I want to see the HK416.  Then again, what would be the point if it's probably going to be a fancy re-skin of the M4? *sigh*