I feel what would make the 10 Civilizations more unique, diverse and feel alittle more like an entirely new game experince is (although conflicting with my Planetary suggestions), instead of "limit" technologies because a Civilization "is this or that instead" because they can "work well under here and flourish on that" they will be vulnerable to Technologies that are only permitted to them.
Every Civilization will have a entirely different Technology Tree of their own and the options to research from their own branches will pop up at some early Techs, advanced, you know. The Drengin will have access to Techs granting them superior WarFare technology, enhancing or allowing such and such..
Darth will have access to such a Theory-Tech, "Mantle Complexes". This is one of the beginning early Techs of their very own that allows them to easily construct Facilities between the Surface & Mantle and Mantle. From here on they will access to Technologies from Industry, Biology, WarFare, Computing, etc. Industry research projects from the Reptilian Mantle Complex theory allows Mantle-Mining, eventually Deep-Core Mining allowing an increased acculumation of credits and minerals!
This is all from regular facilities on the planet, if you construct a Farm, and posse's your Darth Mantle Biology Techs you'd have enriched soil, nutrients being freshly produced and scattered Underground.
Every Civilization from their history, past and their type of species allows them to access incredible Techs only available to them, the Drengin Empire are very Militartisic, Humanity is large and undivided, Computing and Medical Biology open for them, Antaran are proud, intelligent, and Republicans thus allowing a mixed tree of WarFare, Computing, Communication, etc.
