Here are some suggestions:

1. Increase cultural influence by at least 30% or more in a planetary system far away from the home planet, so that this would negate the need to create satellites, or to scuttle those that were created earlier, so that logistic slots can be used for more useful purposes. 

2. I think the mini-government option as a starbase upgrade is overkill and should be deleted since its mere presence should mean that there is already a mini-government in it and that it should scare the hell out of planets with weak loyalty into submission within its effective range, and would activate the enemy AI with high loyalty within the range of the starbase to become more aggressive against it, until such enemies are decimated and conquered.

3. Thus,  it would be much more realistic, I might add, to quadruple the time it would take to build a starbase IN ENEMY TERRITORY, to give the opponent a chance to stop it from being built and for the one building the same to defend it as it is being built. It does not make sense that as something gigantic is being built in your own backyard, you are sorely unaware of it with all the banging, hammering and so on. Thus, it would be logical that once a starbase is in the process of completion, an option to build turrets around it with greater speed would be a logical thing to do as a defense against potential attack.  Of course, these turrets would still be insufficient. There is still a need for one's ships to defend it as it is being built.

The normal rate of starbase building could still be maintained within friendly territories.

This would be much more fun. Reminds me of the Death Star being attacked by the Rebellion in Return of the Jedi.