Why would you believe this? Rand wasn't horrified so much by a world without evil as by the notion that the Elayne who exists in a world without evil wouldn't be the same person as the Elayne who exists in a world with evil.
But even so, Rand himself is a construct of a world that knows evil. A world without evil is completely different from what he knows or desires. But Shai'tan would be perfectly happy with the annihilation or corruption of existence because that is his nature. The only problem is that when he has corrupted or destroyed everything, there will be nothing left for him to destroy or corrupt, but then that's why the Creator exists. It is the Creator's nature to create just as it is Shai'tan's nature to destroy. One cannot exist without the other. Creation without destruction is simultaneously stagnant and ephemeral. Cestruction without Creation is inevitably self-destructive.
Or that's Robert Jordan's theodicy, anyway.
I agree that to a point the Creator is about creation, and Dark One about destruction, but the Dark One isn't mindless, and doesn't seem to want to just destroy everything. In some religions you see the idea of Creation vs Destruction, but often these are represented by mindless entities who can't help what they do, I think if intelligence is there, a force of destruction wouldn't destroy everything.
Lord of Chaos states pretty much the exact opposite:
EVEN I CANNOT STEP OUTSIDE OF TIME. For an instant terrible anger filled that awful voice, and-could it be frustration?
Lord of Chaos, The First Message.
But wouldn't this stand even if he was free? That the Dark One is bound by time, or can end time altogether, but at that point I don't think he would be able to retrieve souls lost due to Balefire either, I see this as anger / frustration at limitations to his power, not at imprisonment.
No. Shai'tan and the Creator are equal and opposite halves. This is largely the point of the final confrontation - Shai'tan cannot be removed from Creation without destroying it anymore than the Creator could. Even if he is removed, he, the Destroyer still wins because Creation has been fundamentally corrupted.
I don't know if they are equal or not though, I get the impression (not backed by any facts admittedly)that the Creator is more powerful, but doesn't want to destroy the Creator, only contain him and give humankind the choice, and I also get the impression despite what Lanfear says that the Creator can't be destroyed by humankind, whereas Rand appeared to have the choice to destroy the Dark One if he wished.
