To elaborate - I think it would be a good idea to build in support to either the mod API or the base game itself for multiple players to control a single empire. Exactly, this would basically be all ships/planets shared between players all the time.
Mainly this would function as a co-op mode where players could have their time freed up to spread the micromanagement of the empire across multiple players. This would allow for more focus on the specific parts of the game that each player enjoys most.
Additionally, this sort of mechanic/api would allow for a ton of new mod ideas. For an example, think Natural Selection (1/2) for Half Life. All players shared the same equipment/buildings but roles were divided up leading to interesting dynamics.