Make Inorganic its own Population trait

With Epistis and Remnants, you would have issues being unable to build new ones. Consider you can only build your original species.

This "inorganic" trait should propably also lock out Horatio Genesplicing those pops.

I fully agree on Biophobic not being a Empire Trait, but a Pop one. Indeed in one game I was using a number of organic pops to "grow" some manpower. And I even planned make a Uniue Planet System into a "foodhouse". Only to learn: Apparently they suddenly really hate crops.

I'd also probably allow players to build Pops that aren't their major pop with such a change. And obviously their stats'd be bumped up to compensate.

Biophobic would fit really well into the 2nd Population Bonus Slot (the one already used for Conditional bonuses).

Of course going into Edit View, I noticed that the Riftborn are already at 60/60 regarding Population. Of course ideally we also want the Terraforming Options to be tied to Biophobic. And it seems likely a Faction Trait is better at doing that. Maybe a mixed case, where the Faction Trait adds a modifier to the Original Population upon gamestart? That could get around a lot of issues.

Honestly the fact that terraforming isn't 2-way already confuses me. And Inorganic would likely have neither a positive nor a negative point value. The advantage of not getting Happiness Penalties for Sterile planets weighs pretty much ounce-for-ounce against the disadvantage of not getting Happiness Bonuses on Fertile planets, as well as having to create new populations manually.

Plus, the Unfallen are already over the Custom Faction limits by themselves, so that doesn't seem likely to stop Amplitude.

I have a idea why Terraforming is not 2 way: The AI needs a point to stop. If Terraforming was two way, there would always be a option for this. So the AI would have issues keeping planets as they are.

You could just have them prefer certain planet types. They seem to do fine with the two-way Terraforming mod I have installed. Horation winds up with a decent number of Desert planets, a few dedicated Fertile and Cold planets here and there, and goes about their merry way. Haven't exactly done a thorough analysis mind but it doesn't seem to me that's the limiting factor.