Ranking up in Halo: Reach requires no skill.
Halo: Reach gives you points in each game no matter how you finish. I think my character is a Lieutenant or something now, and I don't win many games. I DO do better in King Of The Hill games for some reason, but I don't often finish in the top 3 of an 8 person FFA slayer game.
What I am saying is, I can finish next to last in every Halo: Reach game I play, and I WILL become a General eventually. Not that I care, I'm only halfway through the campaign after all this time that the gane has been out.
Starcraft 2 now, THERE'S a game where you will never get to higher ranks if you don't earn it. I was a Silver Terran through most of Season 2, I started Season 3 back in Bronze and am trying to get back into Silver now.