Jean cannot evolve into the Phoenix Force, LOL! You are trying to go by the original Phoenix story while ignoring the retcon. What you are trying to argue hasn't been the case in over 30 years. Also, Morrison clearly established the PF as a separate entity from Jean Grey. She always referred to it in the third person. She even told Emma, "Its just you and me and the Phoenix." Also, CC clearly established Jean as being separate from the Phoenix Force during his second run on the book when he had that D'bari guy come after Jean to avenge his people's death at the hands of the Dark Phoenix. Jean was clearly stated to be a separate being from the Phoenix Force entity.
Look, I understand why Jean fans want to try and make the argument you're trying to prove. Without the PF and without Betsy's powers added to Jean's TP, Jean has never really been all that impressive. She's still a strong telepath without all of that, but she's dwarfed by so many others (Xavier, White Queen, Shadow King, Bogan, Exodus, X-Man, Cassandra Nova, Stryfe, etc.). Jean fans want to believe that she can compete with these people when she clearly cannot. Heck, I'm a Pre-Morrison Emma fan and I like her more than some of the people on that list, but I'm big enough to acknowledge that many of them can best Emma in psi-combat.
Getting back to Morrison, it isn't that Jean evolved into the Phoenix so much that she merely housed it within her being. She was one of the few people around who was genetically fit to be able to house the PF. That's what was special about Jean after the retcon. Read what Ghost Jean told the Phoenix Force in this scan:
http://readcomicbooksonline.net/read...2010/cw017.jpg
Anyway, with the PF, Jean Grey is near-unbeatable. It was also PIS how Xorneto killed her at the end of Morrison's run with that planetwide EMP stroke he hit her with while his powers were amped on kick. Phoenix Force Jean Grey had just gone for a swim in the sun, which has an EM field one trillion times as powerful as the Earth, on top of the large quantities of radiation materials, heat, etc it contained. That EMP thing is something she should have either eaten or not even felt.