[IDEA] Simple way to differentiiate factions.
from 
Elemental Forums
Elemental Forums
This is rather barebones, and shouldn't be the only thing, but an idea.
Each "race" should have a few techs that they have an affinity to. Relias might have it with some adventure techs and hospitality. Procinipee with channeling and civics, etc
These techs, when researched, would not raise the technology level. This would encourage beelining them, but not force it.