Muramasa wrote:But that's the problem. As I see it, Ranma can only cast magic as a girl "just because." Again, I'm not saying don't write a Ranma-chan story. But, in my opinion you should find a different reason for Ranma to remain a girl. Your current plot device is too generic, relies on a deus ex machina and is basically a
hand wave explanation.
*Sighs* It wouldn't be, "just because." For one, it takes into account that people with linker cores/who become mages are rare on Earth, thus Ranma isn't being made special by starting out with one/being one. Two, it offers some credence for why he would have
never been able to realize that he had personal access to magic, and thus make use of it, before the start of Ranma 1/2 (which is in respect to the canon of the universe that Ranma comes from). Three, it adds some dimension to the idea that Ranma can use magic, because he'll care about having to be a girl to use it, rather than there not being any problem at all because he can use magic as a guy (and it wouldn't be Ranma 1/2 if he doesn't end up having to be a girl for something when he'd rather not be).
As for the deus ex machina, I don't see it. If you're referring to Jusenkyo, that's a well-established source of magic that changes someone into something else. If you deny it its function, you destroy Ranma 1/2. Even if I were to use a spring that just happens to endow those who fall into it with a linker core, instead of playing with the chance of a new body having one, it still wouldn't be a deus ex machina because it's wholly possible that Jusenkyo could have that kind of spring.
And we already have an explanation as to why Ranma-chan has red hair (and it has nothing to do with magic). In order for the fantastic explanation to be relevant (magical ancestry etc.), the mundane explanation (she gets it from Nodoka) would have to be debunked. Otherwise it's just speculation and irrelevant.
Wait, we know why Ranma has red hair as a girl? Even though Japanese people don't have naturally-occurring redheads, and neither her father or mother have red hair, much less blue eyes? (Heck, considering Ranma's height as a girl, at her age, she seems especially short when compared to her parents, as opposed to his height as a guy.) Aside from Akane, whose hair can still arguably be considered black, every other Japanese character has black or brown hair, and usually does not have blue, green, et cetera-colored eyes.
I know that genetics plays a role in who has a linker core/can become a mage, or else the artificial mage project would have never happened. Considering how Jusenkyo creates bodies with magic, I don't think it's a stretch to say that there's a possibility for the body to end up being magically-inclined, and thus why someone like Ranma would end up with red hair. Especially since the nyanniichuan spring's change focuses on age and gender, not race or pigmentation. And if the magic of Jusenkyo inhabits the body like a unison device might, which are known for changing someone's pigmentation while being used, there's that, too.
Again, if Ranma can't use magic as a guy than flying is too dangerous. It only takes one inconvenient change and 'BOOM!' Ranma falls to his death due to stupidity. Also if Ranma knows the ki equivalent of the moko takabisha, why would he need a magic version? He already learned the technique. It's redundant. Beyond that, there's not much else I can argue about ki vs. magic until the theoretical limits of both powers are explored. For instance I don't see why ki is unable to do what magic can "just because". The limits to both powers is just too vague right now. Until then, I can't say anything else about it. All I know is ki is vastly different from mid-childa style magic. But that's just the 'what' , I don't know the 'how' or the 'why?' .
Well, flight wouldn't be a problem if he ends up being able to switch between forms at will. Besides, Saffron dropped him (along with Mousse, Ryoga and Genma) from a mountain and he (along with the others) came out hurting but otherwise alright, so death from a fall is unlikely unless he falls onto something particularly deadly.
Also, using a moko takabisha-like technique using mana would not be redundant, unless you think that the supply of ki and mana are infinite. For instance, if the situation called for him to save up either his ki or his mana, then he'd be able to use one primarily over the other, which would be really handy. Plus, the mana or ki version may be more effective depending on the target, so there's another good reason to have both of them to choose from.
Aside from all of that, the story I want to write was inspired by the fact that using ki would be useful in dealing with the AMF, so the use and importance of his ki is what I'll actually be focusing on the most. Though that and him learning some magic come second to character interaction.