Known Bugs:
Some graphics like the magnetic aura will not follow the planet when its type changed. The effect will stay on the planet though.
Planned Features:
1. Find a better pic.
2. A sensible progression of the planet type depending what type it is and what hazard was removed.
3. Spawning of Solar Shades/Mirrors when removing hot/cold
4. Increase the Maintenance of the Structure with every upgrade (I will make it not removable by then too )
Maybe include the source in the mod? That way others might be able to help poke around and see what's causing that bug.
As for the planned features;
1. I'd be happy to help with this if you feel so inclined (whether you mean for the forum page or for the in-game one).
2. This might not be feasible for a single structure, but if you look at how the techmining is done, you may be able to have distinct ones that only apply to (and can only be constructed on), say, "hot" type planets or "cold" type planets based on the conditions. Might even want to do special "terraformed" types that it reaches, rather than going to full Terran.
3. This one's a bit complicated, but take a look at the code used for stations. That's all the advice I can give there, sadly.
4. Not much to say here.