He only restated the same thing if you define "power" as just "mental capacity", which if you do you might as well just say mental capacity.

The problem with "power imbalance" is that it's so nebulous that you can just define it any way you want. A hulk married to an Olive Oil, is the power imbalance in his favor even if he's a lovable oaf and she's a dragon lady? It could be either way depending on which argument you're trying to win.