In no particular order:
1. If the tech allows it, an increase in the zone cap would be amazing. I always have so much fun when 40+ heroes are working towards a common objective, but organization of "raids" takes a lot more time than it needs to because everyone rushes to reserve their spot in the zone .
2. A "butt" slider.
3. I would love to be able to dump market transaction data into a spreadsheet or database to analyze offline. This would be a very low priority for the devs, but I am a data nerd and I think the market would function more efficiently with more transparency.
4. I LOVE outdoor bases. However, the mechanic for making outdoor bases limits the accessible geometries quite a bit. The ability to simply remove the ceiling and walls from an indoor base to access the outside would open up a lot of creative space, especially indoor bases with outside landscapes.
5. It would be neat if there was something (with an incentive) else to do besides raid again once everyone is organized in a league. For instance, double the rewards for a mothership raid in the hour after a hami raid is completed. Or make a successful mothership raid give a 30 min temp power that debuffs hami. Or make either give a temp buff for incarnate trials. The goal would be to maximize the playtime/organization time ratio for league events.