I have been playing halo since ce, i got halo 2 a few months after release and I was hooked. I started playing big team battle and eventually got into playing team slayer. Having a level system like halo 2 added somthing no other halo had, for me it was the reason to play hard and I put so much effort and emotion into playing good it made the game so fun. I was a 28 early in halo 2 and I loved showing it off and I think it inspired other players to try to get good. After the level reset I could have the time of my life if I was on at 5am in the morning with no friends on and just playing rumble pit to get my level up. Later in the game I acheived one of the world first moons in big team battle(level 44). And I also was one of the highest levels in Team hardcore,(46). Yes we did get cheated some, but we delt with it and contiuned playing. I know the person who got the first legit level 50 in team hardcore even though there were cheaters. We need a level system that seperates the skills of players and not just an experienced based leveling system.
On a side note, I have warmed up to the feeling of them incorperating a lot of new stuff to appeal to the new gamers and the mass casual gamers. I feel if we can get tons of active players it will repopulate the halo community like it was and needs to be.