Related: I just spent 2 weeks doing a fanedit of STV. I will die on the hill that the plot is good if you can get around most of the silly humor of Shatner (which obviously I removed), as well as most of the weird shit between Scotty and Uhura.
At the core, it is a sweeping critique of religion and charlatanism. Larry Luckenbill as Sybok is one of the great performances in all of Trekdom.