My love of shooters has sort of been killed off by the whole unlock through level up thing COD introduced. I've always liked the idea of both teams starting off on an even playing field in shooter games like in Halo games before Reach and pretty much every other shooter.
I think it's fine that Call of Duty has a system where you can unlock stuff and level up, it works really well for that type of game. My only problem with it is the influence that it seems to have over all other games in the genre. Now I can't play a game without dealing with other players spawning with different loadouts so that they might have an advantage or disadvantage based entirely off what they choose in a lobby menu.
This is my main issue with shooters post COD4. Even if some games have easy, no skill shooting, at least everyone is on a level playing field.
You used to play games longer to get better. Today, you get better PLUS you get better gear. It's completely backwards.