So, I'm loving the new terraforming system, but I have two little problems with it.
1. The Stellar Reflectors seem somewhat useless now.
With how cheap they are to build and maintain, Terraforming Platforms are like the pauper's choice for terraforming, while Eisen Divisions and Atmosphere Processors are obviously late-game structures meant for the true terraforming magnates who have a bunch of cores and nanoforges lying around. Ismara's Slings are situational, but they can also be really valuable in systems with lots of terraforming going on. Stellar Reflectors, on the other hand, seem too expensive to maintain to appeal to the new colonizer and too ineffective to be useful to the veteran. They do remove Poor Light, bring in more points than Terraforming Platforms, and don't require stations to build, but you were going to build stations anyway, and the slight edge the Reflectors have in point production doesn't really justify their construction on any planet that doesn't have Poor Light.
2. There's not enough incentive to pick worlds that aren't water or terran.
The only thing the less-optimal planets have is that they require less terraforming points, which, if you ask me, doesn't really justify their production over that of temperate paradises which can be further improved with Mild Climate. They take longer, sure, but it's not like the players won't have anything else to do while they wait, and even if they did decide to go for a jungle or tundra world, they would seem like just another step towards terran or water — never the final stop.
I'm not sure if this is feasible, but I think a good solution to both of these would be locking certain terraforming projects behind Stellar Reflectors depending on where the planets are in the system. E.G. A planet that's basically kissing its star should only be terraformable into desert or jungle until it has Stellar Shades installed, while a freezing planet on the outer end of the system should only be allowed to become tundra or frozen until it has Stellar Mirrors. The reflectors would unlock the other types and ideally, they would have to stay up for the planet to be able to continue being the type it originally couldn't.
This would make Stellar Reflectors a lot more useful, while at the same time, the upkeep and building slot requirement would incentivize creating tundra or jungle worlds over terran or water. It would also make the "Goldilocks Zone" system that Starsector seems to have feel more consequential, because with this set-up, the planets located there wouldn't need any reflectors to become anything, making them more precious, just as they would be in real life and Starsector's lore.