I personally enjoy the idea of a new fairy.

I think though, since from what I've gathered from reading live letters and such and I can't quote directly, I think SCH is focusing more on the duality of sun and moon and not the elementals. I wouldn't be surprised if SMN focused on elements and SCH kept to light and dark, similarly to how SCH in XI were focused on the duality of light and dark. I think Selene and Eos will each get new moves that will change how we play when we have each fairy out. Still though, I hope we do get a new fairy, just because. :P