Look in reach the whole game was yeah crap,and then with every update it got better but its still not very good.You should not change the core halo gameplay too much.
With this i dont want to say make halo 4 exactly like halo 2 and 3 but instead of implementing all the changes with the release make 1 playlist and test the new things,then listen to the feedback of the community and look if you can take it into the game.
sounds kinda like a beta but i think it would help.normally you need a beta not to test connection and balance only but also testing the new changes and thats whats missing here.