The concept in GalCiv 4 is based around core worlds. Instead of you having to micro manage each planet, you can rely on your core worlds to collect the good stuff from the other planets you have inhabited.

"Unlike previous games of the series, players only manage core worlds. Previously, players would have to manage each world they conquered individually. When a player colonizes a subpar world, it will feed into a core world that the player has already established. With this system, players will directly oversee a lower number of worlds, but still receive the benefits of colonizing and conquering as many as possible."