I’ll try to be as rational as possible, but there will of course be some repeats.
First I’ll go onto explain Jean’s relation to the Phoenix, and how it differs from other hosts.
Jean first met Phoenix in Classic X-Men (1986) issue #8, and this where Phoenix first introduces itself as an infinite being that is
beyond reality. The part about this that truly matters, is that Phoenix states that Jean’s original body is still alive, and that a piece of her soul
fighting the gift that the Phoenix offered. Meaning that Jean did not fully merge with the entity, and is why she has on the green costume.
In Phoenix Endsong #5, it’s shown that Jean can not only
forcibly remove fragments from other host (an ability never shown by any other host) But the Phoenix mentions that the
two of them are one. Jean also mentions
“little big people” which is what Jean of
earth-15104 went through. So despite those two comics having different writers, events revolving around the White Phoenix are being acknowledged consistently. So using the different writers argument doesn’t apply here. (New X-Men 2001, TPB PART 3)
There was previous mention that Jean displays no transcendence over other avatars, but this isn’t true. In Uncanny X-Men Vol 2, #19, Scott tries to ascend to the WHR but is
denied access by Jean. Not only is Jean in a higher realm than him, but is capable of keeping hosts out if she chooses. This is very consistent with other showings, like in New X-men, the other hosts are simply pieces left behind,
while Jean is able to amputate an entire future. Phoenix reaffirms this in Jean Grey #11, saying that every host leaves a piece of themself in the WHR.
Now I’ll go into admissions by the Phoenix itself. In Jean Grey #11, Phoenix mentions that Jean Grey is the
perfect host, the perfect vessel. Making a distinction between her, and the other Phoenix hosts that leave fragments of themselves behind.
in Phoenix Endsong #5, Phoenix says that the two of them can transcend the
WHR together. Together the two of them can become “Gods.” Something that no other Phoenix host, even Hope (who became white Phoenix, but not White Phoenix of the Crown, creating further distinction between Jean and other hosts.) has showcased. Jean is the only character who can manipulate the
WHR freely, even when it’s just a teenage version of herself.
When Scott meets Jean in 100th Anniversary Special: X-Men, Jean says that she’s just
Phoenix, the embodiment of Eternity. Again showing that she is no simple host, she and the Phoenix are one.
As for scaling the newer showings, the WHR has always been shown to be a higher realm. In “Uncanny X-Men vol 1 #462 ; Breaking Into Comics the Marvel Way #2” as the Chaos Wave was sweeping over the Multiverse, Rachel and Jamie were able to take
refuge in the WHR. I showed earlier that the Phoenix stated that it was
beyond reality as well.
Ewing is simply taking what’s already been established, and elaborating further. There has been no shift in the WHR and it’s place in the cosmology at all. Even between writers, I’ve shown that events regarding the WHR, Jean and the Phoenix are very consistent.
I hope this will be sufficient, I tried to keep it as short as possible. Because again, this was already discussed and approved in a different thread.