No one is saying that they want trueskill exactly like it is in Reach, just saying that trueskill was used in Halo 3's ranked, it was just not emphasized by the matchmaking systems to make sure you get a good skill match. More emphasis on connection and getting you into a match quickly.
What people want is tighter trueskill matches, which doesn't have to associated with 1-50. Halo 3's 1-50 used trueskill, Halo 3's social used trueskill, Halo Reach's Arena uses trueskill, and Halo Reach's regular playlists use trueskill. It's all about how the matchmaking systems utilize trueskill.
Whatever Halo 4 has for matchmaking, be it social and ranked, just one set of playlists, it will also use a form of trueskill. I understand the want for a ranking system, but something like Arena without seasons (or longer ones than one month) is a vastly superior system than Halo 3's 1-50. Arena (once it was moved to win/loss) is actually pretty damn good, its implementation into the game was just really poor.
Also, for anyone curious about Beaver Creek and Penance in the MLG playlist. My results today were six games played, and neither of those maps showed up.