I played this a bit last night. Crusade with stock Altarians and I think default large map settings. I seemed to get pretty far very quickly just building colony ships as fast as I could. There is a quite a feedback going on between colonization and the good ideology bonuses.
Building colony ships as quickly as I could, I colonized the nearby systems, then fed those systems space production back into the home system’s shipyard, for faster colony builds. Each system I colonized gave a benevolent idealogy boost, which I piled into the colonization line of benefits, for more colony ships, more planets to colonize, more colonists on each new planet.
The extra colony ship is fully-loaded, so 5 population, which is pretty critical since I was starting to run out of population to export from my homeworld. Then there is the boost that gives all new colonies +2 population, which also helps with coming up with new population to throw on other worlds (and a big production boost as well).
New colonies give me benevolent points which unlocked the above goodies, but ALSO, because I am Altarian, gives me research boosts, which helps unlock a lot of nice tech to keep expanding.
I guess the idea is that special resource shortages will start to bite later on and keep me from getting much use of the colonies, but I am not short on starbases either, and the colonies have their own resources. I think I am up to 3-4x as many planets as the AIs, which I think will be hard to overcome, especially since I am also leading in tech, production and military power.
Honestly, I wasn’t even trying to push expansion that hard, it’s just a sequence of things that I fell into. I think that even with all the limitations in place, GC3 base economy and other mechanics are fairly favourable to rapid early expansion.
