Improving Governor - assigned city.
I like governors; but having them have to stay in the city to provide bonuses means they can't go out adventuring to gain more levels.
So I recommend borrowing a mechanic from HoMM4 - wherein heroes with the nobility attribute would provide their bonus to a city even when not there; but to visit the city personally to put them in charge.
So for FE; that would mean when a governor is in a city, he can have that city ASSIGNED to him; and then the city gets bonuses as if he were there.
For balance (and easier coding), it's probably best if a city can only have one champ assigned to them at a time. And of course, while he's assigned to a city, the champ doesn't give his bonuses to any other cities he might be in (to prevent doubling up bonuses).
This would allow governors to join the adventuring while still governing; and would be more fun imo.