The genderswapping will never, ever end. Rule 63, etc.
Plus, I really love a good genderswap. It requires a good deal of creativity to change a character while still retaining a good semblance of the original. And it's neat how fans actually, eventually, gravitate towards an "official" design (ala kyonko ).
Oh, well, that's understandable, too. It is unusual, though not that much. After all, Naoto only wears a skirt for all of 5 lines of dialogue, and she's frequently drawn in one. If people like an idea enough, and apparently enough people thought the P4 crossdressing scene was hilarious, people will want to see, and thus create, much more.