I'm referring to the fanbase. I really don't think you can blame the decrease of players on other games coming out. Games come out all the time, why would any game big hugely popular if games are always coming out? People were looking for a new game.
As for change. I'm a proponent of don't fix what isn't broken. I didn't see a need for any significant change from Halo 3. Therefore when HUGE changes came, I wasn't happy. Wouldn't soccer fans be irrate if players were using decoys and hiding behind boulders, jumping off trampolines and so on? Yes they would. They would want soccer back. Sure, some people would be like, "This is hilarious, this game just got a whole lot more interesting." (I would be one of those guys, soccer is boring to me.)
A lot of the reason you like Reach is not because of the matchmaking, which is all I really care about. That's where we differ and that's fine. 343i is aware of this and will find a way to make us both happy. (I hope)