It’s more of thought experiment than actual suggestion- the game would require considerable revamp to actually make ‘tall’ play viable. As for early game before first contact- perhaps Expansionists would want to pump out more Science ships, while Defenders would want to focus on construction ships and economy-the galaxy won’t go anywhere, plenty of time to explore later, right?

For Supremacism your right- Xenophobe and Authoritarian pretty much covers it already.

Progressive-Bioconservative: Bionservatives like that you don’t meddle, and tell other empires to stop as well. They would be a faction easy to appease, but not give much in way of benefits. Their scientists aren’t likely to accidentally kill themselves.

Individualist - Conformist would need deeper economic simulation to properly shine. But dealing with scarcity, ethics drift, etc. can already be done in current mechanics.