I will be quick about this. Get Joseph Staten to write the story. Make an OG Halo and new Halo mode that pleases both pro sprint/anti sprint. Release everything at launch. Bring back either Reach or Halo 3's art style. Make the armor extremely customizable. Keep forge the same, except add A.I. Keep Warzone and reqs because people actually like it, myself included. Add forge maps to Arena weekly or bi-weekly to make the game feel fresh but test it first. Playable Elites, ones that can be shot in the back of the head. Feel free to add anything to the list in the comments. Be respectable of other's opinions though.