For what it's worth, I like the idea of the incubus being its own monster. That the Paizo incubus deals 1d4 Wisdom damage from sexual contact also makes sense, since it's implied they sexually assault their victims, and that seems like it'd inflict Wisdom damage. But beyond that, they missed the mark.
The wording of the whole "kiss or act of passion" schtick, and even folding in the built-in suggestion for more - along with conflicting statements about them being able to change their shape or not - really make it seem like they weren't sure how to present the monster.
The fact that it's also a pretty weak encounter (CR 3) whose only other powers are a handful of utility spell-like abilities (charm person, detect good, detect thoughts, disguise self, and modify memory) and powers (tongues and a 60% chance to summon 1d4 dretches 1/day), really made it an underwhelming entry.