Here's probably a better way if looking at it.
The Creator made the universe and sealed off the Dark One at the moment of creation. Not: The creator screwed up and shoved his mistake under a rug. If the Creator really is good then why have a Dark One at all? Surely he could do what Rand could...
Yet the next words out of you are that Fel was a special guy that we should believe...because he had a theory about a prison. Come on buddy, you are better than this comedy gold.
The creator provides light, and the choice of good. The dark one provides the choice of evil. The creator knows...