On paper, at least, this is something that has a strong phase one dealing with the major limitations of that phase (mineral and energy shortages)
One of the major problems pointed out with Spiritualist is that the ethics divergence bonus only applies to pops that have the spiritualist ethos and conformist trait. You will have a hard time converting anyone else, and overall, this build has the following problems:
- Collectivist can get -35% empire wide ethics divergence, easy, and unlike Conformist/Spiritualist it applies to all pops.
- Individualists cannot resettle (This is what ultimately killed a individualist playthrough for me)
- Hyper Entertainment Forums are not worth it. They were already a bad investment before when every 1.5% Happiness translated to a +1% increase in production. Note that Hyper Entertainment Forums cost 6 energy in maintenance.
- Materialists also get a + Happiness democratic government, given, you lose that if you go Collectivist... but collectivist is kinda needed anyway. Maybe you can get away with going with Materialist/Pacifist/Xenophile for maximum happiness to try to offset the lack of divergence?
- Spiritualist ethics divergence bonus only applies to the pops that have it, you will not be able to convert foreign pops to your ethos very easily.
Overall, I feel that happiness builds in general are going to be quite garbage.
- You need 2.5% Happiness per 1% production vs 1.5% Happiness per 1% Production in Clarke
- Happiness sources were nerfed heavily, so getting to 100% happiness is not as easy.
My thoughts on ethics:
Collectivist - Absolutly necessary if you plan on keeping your ethics under control. The only downside is that it locks the democratic governments. You can probably try to get away with extreme happiness and mind control lasers... but mind control lasers are very late game. Also, gives you access to purge.
Individualist - Would be better if the policy restrictions were not so ugly. No resettling. Slavery is penalized in happiness (which hurts slave/robot builds). Policies are the only reason I do not recommend.
Pacifist - Decent governments, and one of the best ethos buildings in the game. (Note: The real benefit of Paradise Domes is not the +10% Happiness, but the +5% Habitability). The biggest downside is being unable to invade primitives. Also, do NOT pick fanatic pacifism, no matter how attractive that +15% Happiness at peace is.
Militarist - Meh governments. Empire bonus is alright. Building is garbage. Could still use a buffing, but is not terrible anymore.
Materialist - The unique building is one of the best in the game. The ethos bonus is not too shabby. Not worth going to fanatic for, though. Removes all happiness penalties associated with robot policies.
Xenophile/Xenophobe - N/A, more testing is needed and devs confirmed that Xenophobia mechanic is going to get changed again.