What do you guys think about specific game modes named after the Halo title, in which they would be replicating. For example, a H1 gametype with all of the weapons, physics, and general abilities that were originally in the game. So on and so forth with H2 and H3. Essentially make a Halo game that you can always play the Halo you want in the most up-to-date visuals.
This, in turn, could allow for mixing specific weapons from individual games into a custom gametype. Think about having a Halo CE Magnum, Halo 2 BR, Halo 3 Carbine all in the same match battling each other!
Going even further, allow the player to choose from Mark IV, V, V and possibly VII armor for our Spartans. Each having their own shield resistance, recharge rate, mobility assist (speed and jump height), etc… I think this would add an entire new layer of tactics with creating your players get-up.