God isn't really Omnipotent in the preacher verse though. Being Omnipotent is being able to create something much stronger than you, but that's an illusion because nothing is stronger than you.
The Supreme being is the Supreme being for a reason. Don't get it twisted that just because Genesis could rival or exceed God that he is as powerful as God. Maybe in that universe, sure. Take Spawn for example, he became as powerful as God, but God was nothing more than a Nigh-Omnipotent being created by a truly Omnipotent being.
But really it depends on the verse. Omnipotence is really a subjective term, we all know what it means, but it's used so much on nigh-omnipotent beings. Celestialsapien's from Ben Ten are considered Omnipotent, but they're not, they're simply Nigh-Omnipotent because they are limited between their personalities and not being able to manipulate Mana.
Also I'd like to state God in Vertigo was shot by the Saint of Killers and died in Vertigo, you can't kill an Omnipotent being.
EDIT: Transcendent Deity does NOT have to be created, it makes no sense at all.