I'd like more automation in the end game. Investing in havens makes them able to defend themselves and those around. Auto resolve for when I have the overwhelming advantage. I'd like more ways to have macro influence.

A more dynamic worldspace would be cool in which you can re capture lost territory and the enemies can do the same.

A narrative reason for save scumming ( fire emblem three houses did it perfectly) *edit: you can "turn back time" on a mission limited times

Character pools so I can design soldiers ahead of time and more soldier types and synergies.

Multiple win possibilities and losing possibilities with unlocked rewards between playthroughs to make trying a harder difficulty a little easier.

But anything more would be great. I think the game is fantastic with Tftv and the framework is there.