Ugh, what a tough spot. I do not own GS and don't plan on switching over to it, although if you decided to require that DLC, I would be strongly encouraged to get it at some future point. I suppose my not-so-strong preference is to not require GS. As such, I partially agree with Knasp, especially in regards to not requiring more DLC in addition to GS. I'm not completely sold on the idea of requiring GS, but if a strong case can be made that it has features that can enhance the mod, then why not? On the bright side, I have been able to play the current version of the mod by rolling back to the previous version of the game, and it is as enjoyable as ever.