This is exactly the kind of thinking that led to the launch Arena rating/ranking system, which was a hot pile of garbage. The team's performance is literally the only thing that matters because it was, for the majority of its life, a team playlist. That's why there was a separate Arena FFA for people that only cared about their own performance, but nobody gave a shit because the settings were awful (that goes for both Arena playlists, for that matter - it is not a good example of players not caring about rank, it's a good example of horrible gametype settings ruining what could have been a really cool thing). All individual ratings did was encourage you to screw over your teammates by letting them die and mopping up their kill, or sitting back and padding your ratio instead of playing in service of the team. It was, and still is, a horribly shortsighted line of thinking that doesn't take into account the asshole nature of players. Arena was orders of magnitude better once they switched to a team win/loss ranking system. Unfortunately, it was still plagued by a terrible map pool and gametypes that weren't suited to competitive play (mediocre Forge maps and jetpack!), so nobody cared.
As for the instant gratification, I'd personally take a more accurate representation of my skill than have to grind up through the first meaningless 30 or 35 levels like Halo 3 TS until I finally hit the point where enemies could actually hit the broad side of a barn.
