Honestly if they come out with a sequel, I hope we can get some new things besides new charcters. Granted I would love sequel regardless if it was just new charcters, but I just have some ideas that I think would be cool if they did add it.
Like seeing districts change visually due to a factions influence, both before and after corruption. Showing how your actions or the actions of others affect an area, not just through dialogue either. Like a district owned by the player would insect like with webs, cocoons, tunnels. Or if humans play a factor again come back it looks normal, that or more defensive due to either you or the other enemy.
Another idea would be district defense upgrades and sabotage. As in you could build something like a hive, a web, or an underground system to give a specific unit huge advantage in that area. Just as the enemy could make burrows, you could easily sabotage them with something like making the earth collapsing in itself. Cause people to go in a frenzy to destroy it. Or even make the burrow into your prison with spider webs. Just as they could do the same to you by destroying your stuff.
Lastly would be a R&D section, where you could put money into stuff that can affect all your units or the game like a system that helps slow down or halt the corruption system. Or if you upgrade your defenses, the more health you can lose. Or perhaps a failsafe where if you lose a district, the people who took it will not take what you built on that district. (But if you take it back you have to build what you lost from scratch, you know for fair gameplay)
All in all, I enjoyed this game. I wish for the best of luck to the group who made this game, and I hope one day they make a sequel or at least think about it.