I do agree that before they make new styles they should revamp the new ones, but new styles are still an exciting concept. The martial arts style seems the most exciting to me. It would be different from the gauntlets (Beowolf, Ifrit, ect.) since this would be more fast paced, and probably have many 'Crazy' combos.
I also like the idea of a Legendary Style where you use Sparda. It would be like the Darkslayer style in DMC4 but with Sparda.
While the idea I have for a style is a bit un-Dante like, I would like a style where you use Magic of some kind. He could shoot fireballs, and have shoot other things that produce random effects on enemies, blind enemies ect. I just always thought that it would be a cool extension of the fireballs you shot in DT in DMC1 or out of Ifrit ect.