Well CoD is beyond help, it was designed with cheap tricks so any starting player get right into the thick of it, can't fix that without a complete overhaul.
So for some other multiplayer games this could work quite nicely:
- keep kill streaks only as honorary titles (sort of like Unreal Tournament did), otherwise you just got kill whoring 24/7 on all maps and all game types
- map unlockables buyable with points earned for the team (kills would earn little, cooperative kills would earn more and doing/protecting objectives would earn the most)
- have all rewards down to earth, those over the top "I win" rewards really don't anything to the game
So for some other multiplayer games this could work quite nicely:
- keep kill streaks only as honorary titles (sort of like Unreal Tournament did), otherwise you just got kill whoring 24/7 on all maps and all game types
- map unlockables buyable with points earned for the team (kills would earn little, cooperative kills would earn more and doing/protecting objectives would earn the most)
- have all rewards down to earth, those over the top "I win" rewards really don't anything to the game