I think it is a mix of both, honestly. The writers write the freakiest shit one mortal could come up with, and most of the time it hits the spot for someone out there, so they keep on doing itBut I do very frequently wonder who the characters with 8 tits, dick nipples, ear vaginas, etc. are for exactly. Like, are those popular? Is this playerbase freakier than I give it credit for? Or is it more that the writers feel like it and nobody's really complained?
But, yeah, sometimes you just have to look at something that ended up on the game and wonder what on sweet jesus name were they cooking (cough cough Rodenian codex entry cough cough)