Having gone through the vanilla game entirely, I'm going to look into this mod. One comment: your post doesn't actually explain what any of the terraforming stuff is. I was surprised to see settings talking about 400 days to change, 200 days, etc. Also not sure what the Siphon Station and Astropolis station are meant to do. Is the Siphon a replacement for the Gas Giant entirely or just an "extra" volatiles extraction over the completely vanilla gas giant colonization experience? The Astropolis is what exactly? The settings file also has options like Hydroponics and Cloning industries that have no specific information. Without a Readme explaining every option, I'm left to just ask here or literally download and install the mod, then check at whatever point what all this exactly does. Popularity of the mod aside, would be great to have these answered in the initial post.
Did you read the mod features guide in the original post? It covers some of the questions you asked here.
I have a suggestion, but might it be worth considering making a quest line similar to the Red Planet to unlock the terraforming technologies?
He has said he does not want to sideline the stuff into lategame content. Still, maybe have it tied to some easy-ish to medium difficulty missions (maybe tied to the penelope sporeship) with only basic stuff already unlocked? The building BP mechanic seems underutilized.
In a previous version of the mod I had two long questlines with branching paths to unlock lobster seeding on water worlds and gate construction. I decided to remove them for a number of reasons -
1. I'm not an author. Many players probably thought the dialogue and plot were poorly written (although there was some positive feedback too, which I appreciated!).
2. The quest didn't work if the player was using a randomized sector.
3. Once the player completed the quest for the first time, it would be boring to have to complete it again in subsequent playthroughs since they already know everything.
4. Developing quests is extremely time consuming, especially when they have branching paths based on the player's choices. Given the lack of replay value, this wasn't a good use of my time.