goldenarms said:
I'd say that somewhat depends on the story. If it's like, say, Harry Potter, I really can't see why Ranma would need to use magic himself. Unless you're going for comedy (Ranma can cast spells, but they're always randomly chosen for him -- blame the curse), it'd be overkill; Ranma, by all rights, should be able to dismantle most everyone in that Verse, Wizard or not.
No. See, this is how bad stories are made.
"Hurr, I wanna do a crossover, but I don't want Ranma to be too powerful. Hurr, I'll use the most unimaginative and lame way I can think of to prevent that, Durr."
Also, Ranma learning HP magic wouldn't make him any more powerful than he already is. HP magic is mostly a joke.
Ranma can become invisible and rip people's hearts right out of their bodies. He could pick up a pebble and throw it at you with enough force that it'd be like getting hit by a bullet. He can move so fast he can knock out / kill dozens of people in mere seconds.
Compared to that, HP magic is like having a gun fight with Nerf weapons.
On the other hand, Ranma learning magic, going, "Magic? That's so cool!" and gradually turning into some kind of magic nerd could be entertaining.
Not all conflict has to be about fighting. In fact, most conflict has nothing to do with fighting.