As it stand I think this will have to come with some kind of 'colonize dead planets' tech in an expansion, as currently the starting system balance is tied to tile numbers.

It's moddable though, it could be turned in to an Extreme habitat type world that required tech to colonize.

Yes, not the best tech tree, but Engineering + Pragmatic/Coordinated lets you take core world manufacturing planets, and produce ships anywhere in the galaxy.  Thats a very powerful combo which lasts ALL game (Colonizer for example, is only useful in early game, albiet can be OP if you are rushing shipyards, which may be nerfed anyways).