Well yeah, I own all those games, and they did change a great deal from the original, but I also started with the game on PC, played a lot of Custom Edition as well, and I think that releasing the same game in mostly original form is rather shameless. I was hoping it'd be more of a "reimagining" to an extent. If I wanna play the original's multiplayer, I'd do it on my PC. If I wanted the maps to be updated, why not release them for Reach? If I wanted to play the original game, WHY NOT JUST PLAY THE ORIGINAL? It's only ten years old, for god's sake. It's not like people can't just play Halo on their Xbox 360s anyway.
And Halo was great, but it's not like it didn't have massive, massive flaws. The pacing was terrible in some places. If they can find a way to fix that, maybe tell the same story with some of the elements changed, maybe different level design or something, then it'd be worth it. I don't think that they should add anything drastic like ADS or some bullshit like that but a litle experimentation never hurt.