I think it would be cool to have a Halo with an alternative mode or flood mode of a who’s-the-killer game. One person in a party of people is chosen to be the killer or the flood except he can hide his identity and will look like everybody else in the party. The party of people tries to find this killer in their party before all the innocents die. The killer would be more powerful than the regular innocent. You could also add things like missions, buildable items, vehicles, weapons, other aliens/ other roles, and a story. I have seen this game mode in some PC mods and games but never in an actual console based game. It would really be nice to construct a mantis and sacrifice yourself to nuke a buried infested ship but if this game mode would be impossible to make in the next Halo for Xbox One it would still be nice to give a little more leniency with the flood mode options like being able to change the appearance and weapon of a flood.
Any other game modes people would like to see in future Halos?