Instead of having artificial limits just have the tadpole growing be an actual danger. (+the need items to rest mechanic).
Why introduce a mechanic that is disliked by most players? First of all, it is a game and should be fun.
Well the whole game premise is about you having a time bomb lodged into your brain and desperately searching for a way to remove it before it kills you. I'm not saying the game should have hard set time limits like in PF:Kingmaker (which I considered completely fine btw, although the game failed to explain they were in place when it was first released and that could force you to replay huge chunks of the game in order to suceed) just that some limitations for rest-spam whould be implemented otherwise suspension of disbelief is undermined along with internal ballance between classes.