I really liked the Sybok we got. I'm not sure I would have been able to believe Sean Connery was Spock's half brother, much less a Vulcan. I had enough trouble when he was a Scottish-accented Russian defector!
Though there is a connection between Connery and the budget. Paramount was so stupid to shoot The Final Frontier at the same time as Indiana Jones 3. And because of that Shatner couldn't get Connery, and because of that Paramount didn't trust the movie to be a success, and because of THAT they didn't give Shatner the budget he needed. Shot themselves in the foot with that.
Similar things happened with Nemesis. It's like Paramount intentionally wanted these two movies to bomb.