Hmm, maybe I'll add some information to the mod guide about the terraforming system and the limitations. I suspect some of the players who were used to DIY Planets have switched to TASC and didn't realize the limitations are much more strict.
This is actually the first terraforming mod I've used for Starsector, the limitation just feels arbitrary to me since it's just a matter of time and/or scale.
Normal orbital shades dont block enough light to cool the planet? Just make more and/or bigger shades, same goes for heat sources on or around a cold planet.
What about planets with tidal heating (ex. volcanic planets)? Shades will do nothing.
Likewise for planets with no star or a very dim star - more mirrors will not help.
I agree that the volcanic planets would actually be too hot to terraform, but I dont agree that it's because of tidal heating, I'd say it's either from the shear overwhelming heat of the parent star or left over heat from the planet's formation, after all, Earth was most likely once a giant ball of molten rock.
(to really kill the idea that it's tidal heating compare the surface temperatures of Earth's moon with the surface temperatures of any other known moon)
For cold planets, if you dont have a star, make one, or even multiple. If you have a star, mirrors and lenses will work regardless of how hot or (relatively)cold it is, colder stars emit more of their light in the IR range(compared to other stars) which is the part that makes you feel warm in direct sunlight.
You can't convince me that people that can make ships fueled with antimatter and are capable of FTL travel, can't use relatively simple planetary heat management solutions that are in theory possible to make with current IRL technology. For anything people can colonize, whether it's like colonizing a Moon like object or an Earth like planet, heat is the probably easiest part to change at a large scale.