I like the "partially transform" idea but I think its way too much of a stretch for manaketes because that's nothing at all how they work. Yes, they've stretched the line, but not that much. My favorite idea for a new character from FE is Lyn, and I do think she'd be original despite being "just" a swordswoman since she's also got a bow she can use for some attacks but moreso because she's based on the swordmaster style of class, where she'd be about mixing acrobatics with swordplay.
Anna is next if she uses all FE physical weapons (like Robin using swords and almost all magic variants), then probably the FE14 Dancer assuming that's a lance she's got. Similar to Lyn she could be based around a more acrobatic, dance-style of moveset, but with a lance that's a more original and unique weapon.
Overall, though, I just don't care about getting a new FE character right now, especially if we're getting Roy as DLC. I'd rather get characters from a variety of other franchises, I think FE is well-represented with Robin alone.
To be fair, my avatar doesn't quite clear up that I'm a guy, and I do have very long hair right now and one time I went to a stand up comedy routine within the past few months and one of the ushers told my sister (right behind me) "Are you with her?" lol. Its hard to determine who is what on the internet anyway.
Yeah, that's the issue. I see manaketes as an all-or-nothing thing, with possibly the Final Smash being a transformation. Plus, its notable that Giga Bowser, Giga Mac, Lucario, and Warioman all play identical to their normal selves with few differences, they're just bigger/more powerful. Other "transformation" final smashes are either one attack (Ganon, Mewtwo), or the character just flies around and deal damage by touching (Pikachu, Sonic), or only have 1-2 attacks in the transformation (Yoshi, Diddy).