We're rewriting, so we're not constrained by the plot as it stands. I was addressing character issues, which I believe are extraordinarily ill-served all around by this scene, as it stands in the film, without exception to any character present, but especially both Kirk and Spock, with respect to whom it matters the most.
If this gets poorly executed or edited, the scene is a loser in this case as well.
The special effects were weak, sure, but that can be remedied these days if TPTB cared -- which we know they Just. Do. Not.
The more we pull at the many weak and frazzled threads of STV, the harder it becomes to redeem. I try to accept it as it is (which can be hard for fans who have spent decades invested in these characters). If Sybok had been treated as a dangerous meglomaniac and not have Spock so emotionally compromised by his reappearance, the last act could have been very powerful. Instead of a glowing alien freak, instead they find NOTHING. A complete letdown (but the big 3 three expect this, don't they?) It then becomes less about searching for God and more about compulsion and a dangerous cult-like charisma -- in line with Shatner's televangest theme. Now they must deal with a sick VULCAN who is mentally unbalanced and uses his psychic powers to manipulate others to his will. There was a REASON he was banished and exiled from Vulcan. Now we have a dangerous threat to overcome, a 'villian' our heroes must vanquish.
And that Barrier -- they have experience with it, really BAD experience a la Gary Mitchell, which could have been used somehow to help to additionally hinder our heroes. At least it should be mentioned as a complication or fear or something else with which they must cope.
I agree that much more could be done with the 3 diplomatic hostages. Having the three powers work together to recover their people would be another challenge to overcome.
I guess I forgive Kirk rock climbing with no gear -- what? I can't help it, he's Jim Kirk -- but that could have easily been cushioned by Spock acknowledging that he is spotting him with those jet boots. Which of course he was.
The soundtrack is glorious.
I remember noticing the awkward brother thing when I saw it in the theater. It is true that only obsessed fans like me would care about that. I think I retconned it in my head because Kirk did NOT say, "I lost My brother once" -- the more general 'a' gives us some interpretative room there. Yes, Sam was lost years ago and has nothing to do with the movie. It is pretty clear that Kirk sees Spock (and McCoy) as brothers of his heart and he even says so when we talks about having family after all.
I wish Shatner had been less ambitious with his theme, but we are talking about Shatner here, and while I love the guy, he IS Shatner.