Same here mate - I really want to like Natsu (how can they get something as cool as a ninja so wrong??) but she's just so amateurish, and well below the design quality I expect to see from the SC team. It's especially grating because the last game's new female (Hilde) is such a strong, solid design - very grounded but still cool. If you compare the two, it's quite shocking! You wouldn't design a knight in bright pink armour with glittery flourishes, so why the hell saddle a ninja with such silliness??
The 2p outfits for those ladies are silly, but luckily their 1ps are very strong so it's not such a problem for me, I guess. I definitely agree with you about Ivy's Mrs Claus look....
Hopefully Zwei will surprise me with his full story, which would ideally reveal some of the glaring chunks of back-story. The 2p is promising, but I do think he still belongs in a diferent series altogether....