If the Wheel of Time really turns forever, and if every channeler gets a new draw from the distribution of strength with each rebirth, then if the distribution allows for negative strength, eventually there has to be someone with negative strength.

I'm not saying that every channeler does get a new draw, but it does seem like channeling strength isn't constant across lifetimes, unless none of the strong female AS from the AoL has been reborn between the AoL and the Third Age. Or at least between when the AS started keeping track of these things and the Third Age.

I'm simplifying things a great deal, but I know you get what I'm saying.