Oh come on, let Kirk have his weak moments. Forget the hero worship. Kirk didn't ask Spock to do it, Spock knew he never would have, so he did it on his own, after Kirk was asleep. It's been a long time since I've seen this scene, but I think Kirk does say he wishes he could forget, but any of us would. It was the kind of thought anyone in that position would have had. He didn't imagine that someone would actually
erase his memories a minute later!
As for holding up RFM to the very high standards of the fifth ST movie... well, never mind.
My favorite ST moment is in City On the Edge of Forever, in the scene where McCoy arrives in the past. The whole scene's my favorite, but then there's the moment at the end where the (apparently) homeless man fools with McCoy's phaser, silently destroying himself with no witnesses. There are actually more conflicting emotions in that moment and scene than I can think of and talk about, right now.