I’m thinking that maybe there should be a variety of playable characters in h5g campaign like the arbiter, the ONI Spartan, possibly Sarah Palmer? There should also be flashbacks not shown in other halo games, like maybe some of the didacts past, also it would be awesome to play the didact. I think it would be a unique experience to see the story from the view of the bad guys. Maybe you could even fight master cheif in a level, not kill him, just fight him and he gets away. Also maybe make some exclusive weapons for some characters not available to other ones.
Sounds like a cool concept but I don’t think playing as the Didact would be feasible as he is like 15 feet tall or something.
I’d like to play between Chief and the new Spartan, it would be a nice twist to spice things up a little