Okay I sent an idea to the FFMl awhile ago I think, not sure.  

What happens if Ranma is capable of handling for energy ki and chi?  But 
there is a family curse that he doesn't know about until he learns to harness 
it and starts using it for ki and chi blast?  

Say he is as strong as Saffron and Herb but each time he uses his ki or chi, 
he turns into a mouse and stays that way.  Time to return to normal depends 
on how stronf the blast is