The problem with adding skills is that every combat has reactions to every skill.
Basically, adding just one new skill would require adding at least a line or two, possibly more for something elaborate like hypnosis, to every single fight in the game, which adds up to being far, far out of scope.
On top of that, the game is very much a femdom game. Player dominance is… not quite entirely an afterthought (it happens whenever the player wins a fight, after all), but it's still a clear second fiddle after the player being submissive, so between this and the mentioned difficulty of adding any kind of new combat skill, in-combat hypnosis (or player-dominant foot domination in combat) really aren't going to happen.