Make The Arena use MLG’s settings. This would give halo e-sports a great push and satisfy the most competitive gamers.
Make a set of playlists where you start with sprint but certain armor abilities are placed on the map. These would be competitive playlists with cool dynamics.
Make a set of playlists with loadouts. You would be able to choose any armor ability at the start. Invasion would be under this set of playlists. They could even go further by making gametypes with classes (spawning with certain weapons and armor abilities) that work on certain maps (probably the really big ones.)
Make a set of playlists devoted to community gametypes. I think Living Dead could go here as well.
Sorry if I left any essential playlists out. Personally organizing playlists like this would give me exactly the kind of game I want to play, when I want to play it.