Just a few tweaks I hope 343 implements.
-Add some kind of squad functionality to war zone. For example, if you are in a fireteam running war zone have your fireteam call signs be a different color than the rest of your team.
-Let us play all the arena maps on the slayer playlist.
-Change up slayer maps with different power weapon spawns/spawn locations intermittently to change map play.
-When match making solo, match with other solo players to avoid running against cohesive teams.
Let me know what you think and add other tweaks you think of.