I'm envisioning a sandy desert with jackals (or skirmishers) riding on camel/ostrich hybrids. The Jackals with long plasma tipped spears and wearing the whole: Lawrence of Arabia, Arabic gear with the tasseled saddles and long riffles. Sort of, Arabian pirates.

Convoys of wooden Sand Galleons with mortar cannons being raided by sand pirates (I'm thinking: sand and pirates and dune seas).

There has to be other things going on in the Haloverse other than just Covenant digging up ancient horrors. Why can't human crims and Jackal scavenger team up to do piratical things? Deals and double crossings and not a Spartan in sight. let's have avarice drive a game. Adventure and swash buckling. Hives of scum and villainy.

Now I'm thinking of wind whales and sky sharks, floating islands made from junk and hydrogen gas bags. Built by Hugarok and Yanme'e, floating over a world sterilized by the Array firing 100,000 years ago. A world whose technologically advanced inhabitants didn't make it to the ark. Could an independent trader find something of value in the pickings of a dead world? (too buried treasure?) The things that Hugarok could craft from said pickings? Do you take your ship there to get the best tune-up in the galaxy?

The Haloverse was supposed to be big. 343 needs to break out of the buried Forerunner / military honor mold or they will preside over a story-bankrupt franchise.