Also, +2 to Craft is nothing. A sculptor or playwright could get that, more-or-less consistently, by hiring a helper; hell, he could get that by buying a nice pen (masterwork tools, see).
I should think that the bonus would be +1 per point of Wisdom drained (or +2 if he regenerates a point per day); that way, the craftsman would be producing some crazy stuff by the end, just before he was completely insane (again, a good plot point).
EDIT: Also, the format of its name follows the format for subspecies, which insinuates that the Inspirator is a specific variation of Symbiotic Mind. Might we be seeing similar marvels, once you've successfully completed the Dozen Dungeon?
EDIT EDIT: Oh hey, I mistook the intent of the Mind-Feeding ability. That makes this monster a great deal more benign, doesn't it?