^^^ Agreed. I wouldn't even classify Sybok as a villain, per-se, but the best villains are the ones who are tragic figures and don't see themselves as "mua-hahaha" mustache-twirling black hats. I think he truly believed in his quest for Sha Ka Ree and wanted to share his discovery with the galaxy, in the attainment of enlightenment/ascension/illumination. In the end, he was blinded by his obsession, but had the wherewithal to redeem himself with honor, sacrificing himself to save his brother and his brother's friends. That is the definition of a righteous death - something that no other trek adversary has ever done before or since.
And this movie, more than any other, showed the true friendship that the Big Three had for each other, probably the most effectively since TOS went off the air. It is a shame that these great things were completely trampled-on by shoddy visual effects, general lack of production quality and other campy throw-away scenes (Uhura's "Moon Dance", Scotty hitting his head, etc). Definitely a mixed bag, but it contained some true gems in it that none of the other films had.