Hold the phone, I think I'm starting to get an inkling of a clue of what you speak. So like, if, for example, Vedaa realizes that she is just part of this "dream" that the Mr. GodHead is having and that her existence is just a false illusion of His dream, then she'll suddenly go POOF! and cease to exist? Well, isn't that uncreation? And if there's uncreation, then there must be creation. But creation is always using something else for it to utilize so that the process can make something, right? i.e. the arms & legs of the at'Ada.
Or, Vedaa realizes she's part of His dream and believes that even though she's part of Godhead's dream, she still has her own individuality and is not bound to the will of the Godhead, and that she has a choice, and that her existence is real and not false. And that magically makes her more powerful than Julianos or Zenithar?
Creation and annihilation are certainly possible, it's just that when you get into them, you start getting more into the domain of gods, rather than what mortals can typically do, even with magic.
the godhead dreaming is often used to explain all this, so let me try explaining it with another dream metaphor:
Imagine you're dreaming. Typically, you're not aware that you're dreaming, and thus you follow the logic and rules of that dream (the logic may not be terribly logical, but you still go along with it). This is what being in TES setting, and not seeing the Tower, is like: it might all be false, but there are still rules to it that you have to follow, and that would include any limits on what magic can do, and so on.
Sometimes, you'll suddenly realize you're dreaming, and you typically wake up. This is like zero-summing: you have 'woken up', and thus are no longer in the dream (i.e. you cease to exist in the dream).
Very rarely, you could have a lucid dream, this is basically Chim. You realize you're dreaming, but you don't wake up, and thus you don't just get to break the rules, you get to make new rules, and exert control over the dream. Essentially, you become a god of the dream.