[AgentZero]

In terms of Heroes, or more specifically, Planetary Governors, how about a Popular Support rating? Each Governor would have a Charisma stat. Governors with low charisma would give higher bonuses to production etc. but would not be terribly popular leading to lower population happiness, greater vulnerability to subversive acts, and at the extreme (Tyrant) end of the scale, rioting, civil war, and rebellion. Governors with high Charisma, on the other hand, would not give as large production bonuses, but would be well liked by the population, and thus increase happiness.

The Emperor (you) would also have a Popular Support rating which would be affected by how your population felt about their standard of life (abundance of goods represented by large resource stockpiles), their saftey (ships/troops), the economy (number of new/developing colonies), and even things like ethics (if you declare war against an empire that is liked by your citizens, they won't be happy).

Things would get interesting if a Governor's Popular Support on a given planet/system rose above yours, meaning the people of that world/system were more loyal to the Governor than the Emperor. Then you might be faced with the prospect of that governor deciding to break off and form his own empire. You could remove the Governor from office, which would of course cause widespread discontent. Or, you could just as easily have him assassinated and blame a 'popular' empire you'd like to invade. Then your people would be quite happy when you sent the Fleet out to teach those meddling aliens a lesson or two.