squee!
Hmm...I'm thinking it could be a fascinating game to bend the rules a bit and play as a race that was *perfectly* engineered for Titan (by doing the "Create Empire" in SM mode)
Such that:
Methane-breathing (which you can't do with in-game genetics modification)
Gravity tolerance from 0.32 to 0.74 (so Mother Earth will be off-limits with serious gene-tinkering)
Methane pressure requirements from 0.036 to 0.124
Temperature tolerance from -207C to -149C
Max atmospheric pressure of 2.3atm.
Essentially, they'd be an alien faction. I've played some methane-breathers in solo games and it can lead to an interesting sort of co-existence with some NPRs, where they take the N-O worlds in the inner portions of systems, and I take the NH4 worlds in the outer portions of systems. I see a niche for the Titanians as surveyors and miners of those hard-to-work NH4 worlds, trading resources for tech or cash (maybe a Wealth Creation and/or Industrial penalty to compensate for the fact that NH4 worlds are likely to be more plentiful than N-O ones?)
I'm sort of taking some of my inspiration from the Free Drones in Alien Crossfire. These guys have been essentially slave labor for one or more of the corporate factions, and after revolting and disposing of the Garrison Battalion on Titan, they've expropriated all the facilities on Titan and declared themselves an independent world. Though they were careful to at least pay lip service to Terran Imperial authority, to avoid having the Empire drop the hammer on them. For its part, the Empire might see a free Titan as a useful counterweight to the growing power of the corporations in the outer system, and they don't have to worry about them as a threat because the Titanians can't survive on Earth or Venus due to gravity, and would fare extremely poorly on Mars and Mercury because of temperature and atmosphere differences.
I see Titan as either Communist, Ordered Socialist, Stalin Communist, or possibly a Rigid Democracy. That would actually work well with the Wealth Creation penalty, too. What could be better than a Democratic People's Republic of Titan full of methane-breathing Communists struggling against the decadent bourgeois imperialists of the Inner System?