My first thoughts would involve some type of “sleeper cell” covenant rebellion that developed an outpost after the glassing to fight off humanity at the right time. This could reintroduce their species as the main enemy of the game or at least a real threat again.
The point that I’m trying to make is this, it makes TOTAL sense to revisit planet Reach in Halo Infinite if you just simply look at how hard 343 is working to get a game that is over 10 years old now added to the MCC. When the team drops Reach, hopefully soon after more flighting, my bet is the fall of Reach plays a huge part in the story coming with Halo Infinite. I look forward to seeing where the franchise is headed, and a nod to the sacrifices Noble Team made in the next mainstream Halo game is due.And how do you think it can play a major role without feeling forced?
Realistically though, I think Cortana and her AI gone rogue will take center stage in this last act of the reclaimer trilogy. They have to finish off the forerunner’s prometheian story arc. I personally find their existence annoying and really, not all that fun to kill off. So I’d gladly accept the return of the flood to finish them off for me.
Planet Reach could also maybe hold the key to another hidden halo installation? Who knows, but I like the possibilities for Halo Infinite and beyond.
You're about... 2 months too late.
Memes aside, if such rebellion was being built, it'd definitely be noted about. Not all of Reach was glassed nor did all it's Human occupants perish. Additionally, to be a threat, it'd have to be somewhat more dangerous than the Storm Covenant (or Jul 'Mdama's Covenant in official terminology) and the Banished.
The Storm Covenant at it's height possessed quite a large number of ships, including CCSs and maybe even 1 CAS. After all, Jul 'Mdama was a Supreme Commander before the Great Schism.
Realistically, Reach holds no strategic value. All that made it valuable was destroyed (less the Forerunner ship). And, personally, going to Zeta Halo is far more exciting than going back to a glassed planet. As a lore zealot, I'm just anxious to find anything about the Forerunner-Flood war. Documents, terminals, whatever, I just want those juicy details!
For the enemies, I like fighting the Prometheans. Excluding the Crawlers due to their weird hitbox, I find the Knights, Soldiers and Watchers genuinely fun to fight (of course, I'm talking about the H5 enemies, and not Halo 4). But having the Flood thrown into the mix (as long as it makes sense and isn't shoehorned in for nostalgia's sake), would be a dream, seeing how Prometheans were brutally effective against the parasite in the war.
Honestly, I really can't see that happening. If anything, it'd be the Ark or the other Halos (especially Zeta Halo) that'd reveal the Galactic location of the other rings.