I'm just copying and pasting my post from the Most Controversial X-Franchise opinion because of Johnnysv5's idea for the Phoenix and Jean.....because ironically, its actually pretty similar to one of the original ideas for Jean and omega mutants in general when they first did X-Men Forever in the 90s. Putting it here since not everybody goes into that thread obviously and its relevant to this particular discussion, I feel:
My controversial opinion on the X-Universe was I preferred the take where the Phoenix was always Jean and Jean was always the Phoenix. It was the basis behind the original X-Men Forever miniseries establishing omegas, and why Bobby was chosen as the other original omega aside from her. Basically the idea as I understood it was that the Phoenix was always the ultimate evolution of Jean herself, what she could grow to become in thousands of years, kept alive via her own mutant power and telekinetic control over her molecular structure and her psyche, until a point where she transcended the need for a physical body and just existed as the Phoenix. But as for the Phoenix existing in the past.....that's because Jean's ultimate omega potential was to exist as an entity of pure telekinetic and telepathic godhood anywhere in TIME and space. Because see, Nathan and Rachel inherited her powers.....and the idea was that Rachel's chronoskimming power, to psychically see through time, was supposed to be rooted in a latent aspect of Jean's own powers, something that would unlock with her full potential.
And thus that's how Jean would become the Phoenix but still exist millions of years in the past, and be the basis of the Shi'ar legends and all that, etc. And its ALSO why she and her descendants are the prime 'hosts' for the Phoenix.....because when the Phoenix 'possessed' her, it was really just Jean's fully evolved and transcended self REUNITING with its own initial human existence....and in the process being reminded of human wants, needs and concerns, what it was like to be human, something the Phoenix had forgotten due to its endless eons of existence. And similarly, when it bonded with Rachel, it was the connection to her daughter that Jean/The Phoenix was resonating with. That's why even though the Phoenix has always been hosted by telepaths, seeking a symbiosis with mortal minds that reminded it of its origins, Jean and Rachel were its 'true' hosts, because they were of it in a way no one else was.
And then that's also why Bobby was chosen to be the other omega mutant, because although Claremont created The First Fallen to be the Phoenix's opposite, the idea at the time that making Jean and the Phoenix one and the same was what was floating around the X-office, it was Bobby who was intended to be its opposite in that way......because Bobby's full omega potential isn't making ice or controlling water, its essentially.....stopping energy, taking it away. Ending things.
See, when X-Men Forever first floated the idea of omega mutants, it was in a story with Celestials, and the whole idea was that omegas were the ultimate culmination of the Celestials' experiments on Earth. They were the point, the end goal. Beings who would someday evolve to take the place of the current Abstracts like Oblivion and Death and become the mechanism that would end this universe and start the next one. Jean as the Phoenix and Bobby were the fundamental starting point/lynch pin of that concept, as at their ultimate evolution, millions of years in the future long after they'd transcended existing as mortal bodies and were just pure power and consciousness.....Bobby would be the inevitable heat-death of the universe, the one who finally just said to all things "Stop" and ground the mechanism of the current universe to a stop, all that is ending with the absolute death of heat, which is of course just the result of molecules in motion and without it, molecules have no motion and nothing anywhere moves or does anything.....and then his counterpart, Jean, the Phoenix, was the spark that would take the graveyard of this universe and use it as kindling to ignite the next Big Bang, birthing the next universe. With whatever other omegas existed/transcended by then being the only other things besides them that would survive, and then they'd be what created the mechanisms of the new universe and becoming the Abstract/Framework entities of the next universe.