"God" is Gary MitchellCould a big rock really kill a being that was shown creating life? Perhaps Dr. Dehner came to as Mitchell was climbing out of the grave, and she decided the only way to stop him was to transport the planet into the center of the galaxy, past the barrier. The barrier was actually a hole in the galaxy, where Mitchells' powers were greatly diminished. Upon seeing that the Enterprise could penetrate the barrier, he immediately wanted onboard. That's what "God" needs with a starship.
Kirk's pain is a fear of dying alone.Kirk mentions it during the camping trip at the start. He knew he wouldn't die, because he wasn't alone. This fear could've been creeping up on him since David was murdered, when Spock died, or even before that as part of his mid life crisis in Wrath of Khan.
"God" is an imprisoned Q.Well, it's as good an idea as any.
The whole thing was All Just a Dream after all.That's why the whole thing is so totally ridiculous, and explaining the Canon Discontinuity- as well as, possibly, why Kirk (as is alleged) reaches near Mary Sue levels. Kirk just dreamt the whole thing.
Spock and Sybok were actually pretty close before Sybok was banished from Vulcan.Given his acceptance of feelings and his general good nature, it seems reasonable that Sybok would have gotten angry at the Vulcans for tormenting his younger brother. Spock would probably have felt secretly grateful for having one other person besides Amanda who didn't consider him a freak. This would also explain Spock's reluctance to shoot him.
God is a Time LordI mean, why the hell not?