As for 'baseTerrain' I have wished for something different but with a similar objective: being able to determine Base Defense terrain depending on the globe texture, as the current nightlies allow for alien bases. In short, there would be the vanilla Base Defense + modded terrains that could be used for base defense, depending on the base's location on the globe. Since each texture would have alienDeployments assigned to it, you could have the vanilla underground base, or a version of it with a ground level, or even a base fully on the surface.