But Jean and the Phoenix DID do that on screen. Hell, the Scarlet Witch has done that. They've taken the universe and said "Do this" and it was done.
Nope. Phoenix's best feat is altering a timeline. Wanda's best feat is house of M and "no more mutants"- both of which were flawed feats, as the house of M reality eventually broke down, and there were certainly still mutants left, some of which managed to repower themselves through various means. neither one is really on the level of shaper of worlds, which is a severely powered down cube being that alters reality on a planetary level (it wiped out 2/3rds of the andromeda galaxy at it's peak), or franklin richards who was willing entire universes into being as a child...and was only
potentially celestial level at that point.
Hell, you could even argue James Jaspers is more powerful. The earth-238 Jaspers warped his reality so badly the universe of earth-238 had to be annihilated completely to stop his influence...and the "mainstream" 616 version of jaspers was so strong that even that wouldn't have worked.
There are no on panel feats by wanda or any incarnation of the phoenix that come close to this. none. Find one and I'll freely ban myself for a month.
I get that their some kind of lame hierarchy in the way that Aristotle said that men were higher than beasts and beasts higher than plants, but a beast can still royally wreck the day of a man.
i'm not here to comment on whether the heirarchy is lame or not- only the fact that it exists. Celestials are subservient to the abstract powers, and outclass cube beings, omega mutants, and "gods" by several orders of magnitude. The powers of "gods" or omega mutants are meaningless at that level- They created the mutant, eternal, and deviant species in the first place, after all.
When the Phoenix FIRST came out, there was none of this BS like the Shi'ar hurting it. Hurting, not killing. Their best weapons worked out to hurt it once, and even then all they really did was make it break up for a short while. Here we are, several years later, and the Phoenix is back in action. In fact, most of the times we've ever seen the Phoenix fall, it's because Jean allowed it to happen, and when Galactus defeated Jean, he pretty much doomed the universe in so doing.
all you're doing is proving my point. the higher powers cannot be injured or affected by conventional weaponry. The combined power of all earth's godly pantheons concentrated into the destroyer could not hurt a celestial, and the destroyer was obliterated by a fraction of the 4th host. The phoenix is a powerful entity, but only one of many that rank lower than most abstract powers. Compare for instance what the phoenix is capable of to what Abraxas or the Chaos King were able to do- and remember that the Chaos King was only
one aspect of Oblivion, and Abraxas is contained by the power of Galactus.
So sure, the big, stupid, useless characters who never do stuff like The-One-Above-All could wreck the Phoenix, but she's still using power the Watcher calls Second to The-One-Above-All.
The watcher never mentioned the "one above all", since that entity didn't exist at that point. (the non celestial TOAA is a fairly recent invention by editorial) Hell, even implying it's on the level of the tribunal, or the infinity gauntlet is LOLworthy. All he mentioned was the power of a god- and there are MANY of those. A mistake you may be making is that you assume the term "god" means something analogous to the Christian God that's supreme over all others- Marvel doesn't have one of those (DC does though, with the Presence that is clearly an analogue of the christian God) only many different powers that are supreme within their own areas, and the Tribunal to render final judgement. The tribunal serves a higher power, but that entity's motivations and origins are left deliberately ambiguous. We DO know that whatever it is isn't responsible for creating the multiverse as it exists, since the Infinity Being/Nemesis is the only one to make that claim. (and that's the reason why the infinity gems don't work outside of the marvel universe). Whatever TOAA is, it's function is not "god" as DC's presence is, and no one refers to it as such.
Thor is a god. Odin is a God. Cyttorak is a god. But there are three very distinct power levels between the them, and all are far, far weaker than the higher powers. According to Merlin, Jaspers had the power of a god as well- but was still nowhere close to Abstract level as he was eventually killed.