I wonder how much attention to previously established "lore" regarding armour customization 343i will pay.
For instance id love to see Older Mjolnir helmets and noble team helmets selectable to customize my spartan, Ideally id want to be able to recreate noble team and older generation master chief models as accurately as possible.
Im also curious about Customization DLC, it looked like they wanted to do something like this with Halo Reach (GRD) but for what ever reason where unable and we know from bungie that it was possible but very hard to do with halo 3, i really hope the necesary changes have been made to allow something of this nature.
Spartan Ops fills me with hope, while i understand the concept as basically "Spartan IV away missions" if the content is a fresh download each month and not on the disc (which i wouldnt have an issue with if it was) then id love to see it expanded beyond "S4 away missions" into something that could tell various short stories from the universe.
Playing as multiple characters such as The rookie or Thom or Buck, hell we could even have missions like Johnson escapes Halo, I understand these would require more work on the player character side of things but Halo 4 could allow for entire story based expansions on while all the multiplayer guys likely wouldnt really care i know myself and alot of other fans would get a kick out of that.
For example "RAAM's Shadow" DLC for Gears 3 was some of the best DLC iv played to date.
Another Random thought, I really really really hope 343i nail the brute design and keep it fairly consistent between Halo 4 - 6, Armour changes are fine but between 2 and Reach the brutes had a hell of a change from, Hairy wookie monkey to well groomed apes with beards to bald space rhinos with beards