A a half-western Japan-inspired RPG would be great. No classes, though.
Another thing that would be great is the implemenation of fighting styles instead of classes, i.e what kind of weapons you use and how you use them. So if you have trained a lot during your youth with, say, kodachis or any other short blade, you'd be fast and highly defensive, giving you a large advantage over longer blades but making you loose some of your reach in battle. It would also be nice if you could combine some of your weapon profiency with some skill in a martial art or two.