Think about all of the things he has seen, all of the worlds he has explored, all of the green women he has slept with, and when he is faced with death, it shocks even him, to the extent that all he can say is, “Oh, my.” I’m not sure how popular this scene is among the Star Trek Zeitgeist, but I imagine it’s probably hated. I, however, love it. Feel free to tell me how I’m wrong in the comments.
I don’t disagree with you, but I think Kirk was probably the most “human” of the Star Fleet Captains. Sure, he was larger than life in some respects, but he was very grounded and his character flaws were all human traits. Giving him a human reaction to death suited him well, I think. Sure, we all want Shatner to ham it up and give us some spoken word space poetry, but Kirk was human through and through, and I think his final words reflected that.