It's one thing to hope against hope but...from Jean rejecting the Phoenix, to everything Aaron has and is doing with it currently, to Jean's pointed declaration in XM 11...this X-Editorial Office isn't planning on reclaiming that flaming fowl anytime soon. (Thank the Goddess!)
But if you're patient, perhaps a good writer in the next era will make it a pox on Jean and the X-Men once more.
That said...if-IF! I had to advocate for one person to harness the PF again it would have been the one person who claimed and controlled it for far longer and arguably far better...Rachel.
(It's my head-canon that Claremont did with Rachel in Excalibur what he wasn't "allowed" to do with Jean in XM...and why Rachel had a better run-time with it)