1. Allow ships to form fleets with a starbase. When attacked, a starbase or a fleet with a starbase shoots first. As for what logistic value to give a starbase, it's hard to say. Zero? Six?
2. Remove the Orbital Fleet Manager improvement from the game. Allow ships on a planet to form fleets as they would in empty space. Like fleets with starbases, fleets on planets would shoot first when defending.
3. Allow fleets to leave planets in any direction.
These changes aren't trivial to implement (as they involve adjustments to the AI), but I think it would improve the balance of the game. Maybe something for 1.3?