I think the best solution would be jsut to get rid of this "yellow orange red" square thing. Lets say the "enhance" tag determindes how many tiles will get usable. So soil enhancement says enhancementlevel 1 and it will add 1 usable tile to the planet, terraforming for instance 3. This way, we would have our better terraforming options. To stick just to the planetquality ability is silly, as it adds PQ to all worlds as soon as the tech is invented, we want to "terraform" at our own, the worlds we want. PA0: I would suggest to make it possible to build "outposts" on PQ0 worlds. It could be just a simple initial colony, but as there are no tiles, it cant get upgraded until the first "terraforming" techs are invented. The initial colony just cost some cash and will never pay off, until terraforming. To terraform gas giants is quite "uneffectice", but for this the game can check for world size. The gas giants in GC2 actualy are 0.60 of the size of the star