10) A juicy tidbit: an "old school" Aes Sedai, who is also old, never reached her full potential. No clue who this is, but it can be worked out apparently.
(Disclosure: I barely care at all about power rankings, especially when we start getting into bell curves and formulas. I'm more interested in who this person is)
An old Aes Sedai who never reached her full potential.
So I assume we're limiting ourselves to typical Aes Sedai, that is, women who were in the Tower before all of this Dragon Reborn hullabaloo.
In order to reach your potential, it mostly just comes down to "using the Power," right? The more Power you use, and the more often, the more your talent grows.
We also know that an Accepted does not have to be at full potential to be raised to the shawl. (In New Spring, I believe Moiraine comments on the fact that even though one day she'd be more powerful than many other sisters, at the moment she was not)
So, an Aes Sedai who doesn't use her power much... a White, maybe?