Getting a new fairy is redundant. Just add to what the existing fairies can already do. Selene especially may as well not exist compared to Eos, so it would be nice to see some buffs there.

And yes, asking for a new fairy is like asking for a new sect. It's not happening.
In both cases, what could, and probably will happen, are the sects/fairy being absolved into one. With slightly weaker effects.