Command stars have nothing to do with influence, your power does. How much power your faction leader has determines how much influence he wields.

There are also two schools of thoughts on heirs: Grooming or Pruning. If you’re playing a small, GA oriented faction, pruning is the way to go. But if you plan on forging an empire you’ll need all the generals you can get so groom them. Just assign good governors and build up your generals. Your king can be a -1 star, weak attacker, poor defending coward but your three 9 stars (most likely descendant from royalty will be doing the fighting.

Your faction ruler’s stats are really insignificant if you’re forging an empire, just make sure he doesn’t have any happiness reducing stats.