What would you do with the transition between rightswing and the other attack directions? Right now "hand-order" on the haft remains constant between them all (which may be to blame for the awkward animation in the first place?). With the new rightswing and the old everything else, you have to switch hand-order, which, as far as I can tell, would involve letting go of the haft momentarily with at least one hand. This isn't necessarily a bad thing, just wondering how it would be handled.
Random thoughts:
Have you considered changing the overhead to the same grip as your proposed rightswing (i.e. right hand closer to the head)? If the rightswing does end up being changed, I think that would make more sense visually. Also it sort of gives you a "balance" of two attack animations using one hand-order and two using the other.
Have you played around at all with the idea of an attack animation that starts with a wider grip that narrows as the swing progresses? Found this video where they seem to do that quite a bit: