I appreciate that, especially with respect to power balance. But there's also fun balance. I've played (and made) games where characters have powers, skills, or traits that don't get used or referenced much or for whatever reason aren't as much fun as others.
I think what you have actually does look pretty balanced, but, say, The Oak only allows your specialty to come into play when you die, which might never happen.
Indeed, but with that power they can take risks nobody else can. They can risk death on purpose. And I think that's powerful. Since it's also get replaced with a different power once used they don't loose out on anything long term.