The problem I had with Halo 2's single player was also the lack of missions that I really liked. From the people I've talked with, Assault on the Control Room was their favourite level in Halo 1. Give me a level like that in Halo 2.
Another problem was some of the levels were either too long or too short... and then, with multiplayer, you have annoying kids on there who make you want to strangle them.
-puts on heat shield- I’m ready.