Does her natural form have a duration? Erm... nope. I could place a limit on the time she can spend in humanoid form, but... that would make her more dangerous. That's why I had that tidbit in there about committing to a form to give the decision gravity. She has a cooldown once per day on shifting. That will occasionally trap her in a form she'd rather not be in.
Shall I bin the dexterity too? I'll ditch the dexterity.