If you mean what would sway us to matching acts, then you mean morality is what we would want if we had thought everything through. But if you instead mean what would sway us only to assent that an act is "moral", even if we are not swayed to act that way, then there remains the question of what exactly it is that we are assenting.

I'm not sure how coherent the second is. I would tend to think that our beliefs and our actions would converge, if you took the limit as wisdom approached infinity. Perhaps there's no guarantee, but it seems like we would have to suffer quite a lot of cognitive dissonance in order to fully accept all parts of an infinitely wise argument that something should be done, while still doing nothing. Even just thinking and accepting such arguments is doing something. Why think in the first place?

Perhaps I'm missing something, but if I condition on the fact that such an infinitely compelling argument exists, it seems overwhelmingly likely that anyone with the values being appealed to would be strongly compelled to act. Well, at least once they had time to process the arguments and let all the details sink in. Perhaps there would be people with such radically twisted worldviews that they would have a nervous breakdown first, and some might go into total denial and never accept such an argument. (For example, if they are stuck in a happy death spiral that is a local minimum of cognitive dissonance, and also requires disbelief in evidence and arguments, thus making even a globally minimum in cognitive dissonance unappealing.) But the desire for internal consistency is a strong value in humans, so I would think that the need to drive down cognitive dissonance would eventually win out in all practical cases, given sufficient time.