My favorite part of the episode was the Kirk/McCoy argument in the cave. But I tended in general to enjoy those two locking horns over an issue. It gave their relationship a nice depth.
I'm sure Kelley loved scenes like that one, and his big jail cell argument with Spock in "Bread and Circuses."
Somewhere or other, I read Kelley saying that he was eagerly looking forward to a big argument scene with Shatner in ST:TMP, but Shatner kept putting off their rehearsal, and Bill finally got the scene canceled because Kirk was coming off bad enough in the story as it was.
Kelley might have thought it was Shatner's vanity, but I agree with Shatner: Kirk should not be made to look bad.