I want to separate the generic XP pool heroes currently have into Governor XP and Commander XP. The current system encourages specializing in one or the other by making every skill point more expensive no matter where it's placed, and it feels weird that currently the best way for your hero to get better at leading fleets is to spend all his time governing. If you separate them into different XP pools & skill trees, in a pinch you can turn a Governor into a Fleet Commander, have him gain 3 Commander skill points in the XP it would take him to earn 1 Governor skill point, and have a more well-rounded hero.

There could also be special skills you can only invest points in if you're at a minimum level for both Governing and Commanding, to encourage more well-rounded heroes.

This sounds like a solid idea to me, would allow heroes to move fluidly to whatever role they're needed most in, in and out of war which is a nice idea.