FFXV probably won't have loads of spinoffs because it will be close to the end of the PS3's life and they will be focussing on FXVI for PS4 and announcing the new online FFXVII.

I'd hope by the time FFXXX is released society will have moved on and making an adult themed game won't be seen as such a horror. They could do wonders with technology by then. The characters will look life-like, you'll have 3D and you'll be able to hook some device up to feel the game world. Certainly one for those without girl/boyfriends.