THe serious was simply put utter crap, its built on teh foundation of the Phoenix force being a force of destruction.
That is utterly a lie. THe Phoenix force is not nor has it ever been portrayed (at least until quite recently) as a force of destruction.
THe Phoenix entity, as been sentient during a brief period while Rachel healed, and it never wanted to cause harm.
Just because a Jean Grey wo was driven insane by Mastermind used the Phoenix force as a tool that could cause harm. But only after being altered by mental manipulation from another.
Rachel who had a terrible, brutal life when she briefly had the full Phoenix force, never lost control.
We have had people who were insane who had it, people who were power hungry who had it and they used the force and it caused damage, but the force in and of itself is not out to cause harm.
Since the book's basically utterly ignored this, the whole premise collapses.
Let alone, the idea, the very idea that people could choose whom the Phoenix force would bond to. Laughable.
That it would pass over Rachel, Or that Rachel even had the ability to deny it, is laughable.
Why the hell is it so hard for writers to pay attention to the history of their own universe.
Especially with all the numerous ways there are now to get a large amount of backstory and in a quick period of time. Its not excusable.