You can read about how Call of Duty: Black Ops II changes multiplayer class-selection with the introduction of a pick-10 system. It's all explained right here. Or you can just stare at this board game prototype of the system from the creators of the game.
The only thing that would make this better is if this board game was the only way to pick your Call of Duty class and all of the load-out items were actually Skylanders-like statues that had to wirelessly communicate with the board. Right? Right??