I’m thinking season pass, cortana AI chip, medical report on master chief,briefing for agent Locke and a soundtrack.
I’d like it if we got Locke’s journal, similar to Halsey’s journal we got in Reach.
But I don’t think Locke would have a journal, so that goes out the window.
Well in thinking like instead of a journal more like a briefing from ONI.
I’d like something entirely more practical and entirely more awesome. Bacon would be a good choice but I’m sure 343 could come up with something else that I’d actually want to use/display. 
A replica MA5D or whatever the new assault rifle model is, I know unlikely but still would be cool.
Chief’s cloak.
But in all seriousness, I’d like to see a field report of Agent Locke’s career that shows his previous assignments.
I would like to see if there will a flaming helmet like in reach or better yet a flaming armor set as well or weapon skin.
A badass armor effect. Nothing ugly like pestilence, nothing cutesy like flying hearts or silly like Birthday party.
i have the best idea! what about including TERIO?
I don’t really enjoy playing legendary (too challenging, not fun dying every 3 seconds), so I think that all the in-game items should be unlocked through heroic. Heroic is how Halo is “meant to be played”, after all. Achievements or avatar items I could care less about.
We are talking about the edition you know collectible edition I just didn’t have enough room not the difficulty lol
I like your content, but would add a statue (maybe of the main characters) or Agent Locke’s helmet (like H3 legendary), a patch, and it all comes in an ONI collectible box.
There won’t be a legendary edition, but I’d say no exclusive digital in-game content, music (just release it all on the bloody soundtrack), or story content (seriously, that would not be cool). Anything else is fine by me.