2009 Lexington signing:
Q: What are the upper levels of magic?
A: There are none, if the person has enough juice. If someone was strong enough, they could completely rewrite reality.
Now that Harry has used magic in this book without and tailismans, will he be a stronger/more adept wizard with his magic in the next book?”
Harry really hasn’t gotten all that much stronger since the series started. He’s gotten more efficient, more skilled, and smarter, and inasmuch as that makes him more powerful, that will continue. I mean, what doesn’t kill you only makes you stronger…
Oh wait.
Given these two WOJs, here's what I think.
A wizard with a large enough tank can change reality. There are different ways that could be done. Everything from "warping" reality to the point that it changes permanently, to going back in time and changing "reality".
However, it also takes skill and that comes with time.
All that being said, it does not answer the question about Transcending Mortality.
I don't think either of those WOJs answers THIS question.
I don't think the simple use of magic, no matter how much you use, will cause you to jump up into divinity.
I think that a wizard's ability to do god-level magic stems more from the nature of free will than some transubstantiation.
All of the god and god-like beings we've seen, and all of the WOJs that apply, all say that with greater power comes more and more limitations to the use of that power ... except for Wizards.
A wizard can continue to gather power and retain their free will. So they are the most dangerous power-slingers in the universe.
Uriel CAN destroy galaxies, but doesn't.
Mother Winter is pretty much limited in that she can't even come to the mortal world without risking destroying it.
Mab has stated her limited nature.
We've witnessed some of Molly's limitation.
So, I don't believe that a Wizard would automagically become a god by simply sliging about mortal magic.