I'm trying to recall a fic where Ranma gets sent to DBZ after being memory wiped and hit with the moxibation weakness point.
He winds up being found by Grandpa Gohan, and becomes Goku's big sister since they don't know if he's a boy or a girl. The curse may have been locked as well, or the full body cat's tongue might have been in effect without the phoenix pill.
What I do know is that Ranma is able to regain her strength by gradually building it up. Eventually the memory wipe is undone, but not until many years later, possibly at least a decade.
The fic has Ranma and Goku grow up together, and Ranma somehow has Goku treated for some learning disabilities that makes him less of a clueless idiot savant. I believe Goku winds up marrying Bulma, but I'm unsure about that.
Finally, I believe that the fic turns out to have some kind of time loop in that Ranma's future self somehow goes back in time and inflicts the memory wipe and moxibation weakness point on his past self.
I don't recall a lot about the fic, hence the desire to reread it. Somebody on another forum asking about DBZ/Ranma X-over recs made me think of this but I couldn't find a bookmark to jog my memory of what fic it was.