I will tell you exactly what they need to do to make Halo 2 Anniversary successful. Absolutely nothing. Convert the game as is from original Xbox to X360.
Look, I know I sound like someone living in the past, but people who PLAYED Halo 2 for a sufficient amount of time love the game. You say you hate the glitches, come on, be honest. If you were bored, didn't wanna play matchmaking what did you all do? Butterfly, rocket lunge, or hunt down the rare "golden warthog". Oh how naive I was.
The online play was the best by far of any game, and the final patch introduced made it even better. We didn't need kill streaks or armor bonuses; we didn't even need sprint! The maps had an even balance of both big team games and maps for team slayer. Assault was actually fun on Containment, Capture the Flag on Relic was out of this world. Heck, who doesn't miss Turf; by far the best map for not only slayer but 4v4 team games.
I don't care about the graphics, I just care that they stick to Halo 2 and keep it the same. I know this is only a pipe dream, or just call me a old Halo 2 veteran living in the past, but Halo 2 is by far the best Halo multiplayer experience created.
I know I'm probably going to get flamed for this post, but I was one of those Halo 2 protesters, when they shut down the servers. I sure I don't stand alone, however, with my comments.