I spoke about this as an aside in another post. But it requires its own thread.
From the middle of the game onward, I find myself usually cranking hosts of constructors to create/improcve starbase. It's so mauch that moving the constructors around and selecting the item to improve in the starbase becomes more than 75% of everything I am doing. This is because:
1) I have to remember which Starbase can still be improved, so occasionaly I have t check starbase before I send constructors
2) Once a constructor has reached a starbase I must order the upgrade
Point (1) could be adressed by assigning sponsors to starbase. And as I believe that shipyards should be upgradable to starbases (and then unmovable), this could fit well... A planet would sponsor either a starbase or a shipyard.
Point (2) could be be addressed by have a construction queue in the starbase, so that you're not bothered everytime to choose the next obvious improvement.
Yves