1. Host migrations need to go. Not a tech expert to understand how things would need to be reworked to fix this, but host migrations break everything, from game flow to buffs you spent the whole mission building up to actually just breaking the game to an unplayable state. Open world in particular is straight up unplayable in random squads.
2. I'd love to see Archwing get more attention. There's a very small selection of Archwing missions available for one, but even in open world they're basically just fast travel since there's always some "delete Archwing" attack rendering them unusable. I want to rework a few systems related to atmosphere Archwing. Archweapons need some attention too. Archguns being usable in most missions is nice, but the "heavy gun" feel is lost when thier modding options are so limited regular guns tend to be more effective, they could use some Galvanized, Primed, or other mods to even thier potential with the main arsenal. And archmelee is literally never used, at least let Necramechs use them.
3. It'd be really interesting to have some sort of creature encounters, like a yeti on Venus or a sea monster on Uranus. For example, regular missions have hidden traces of them that you use to gather information which unlocks one or two missions where you track them down.