Much has been said about William Shatner's ego and his larger than life persona, especially from his former co-stars. But, according to Deborah Arakelian, who was a production assistant to Harve Bennett during the filming of Star Trek II: The Wrath of Khan, nobody equaled Nicholas Meyer. Arakelian's claim, recorded in The Fifty-Year Mission The First Twenty-Five Years by Edward Gross and Mark A. Altman, is that "Nicky is larger than life. His persona is much larger than Bill's."
Meyer was hired to direct The Wrath of Khan and ended up rewriting the script as well. Meyer wrote a story that everyone loved. Even Shatner admitted "we were in love with the script and impressed by his creative ability." And no one requested any major changes because of that love.
According to Arkelian, it wouldn't have mattered because "no one tells Nicky what to do. Bill could have tried, but he would have failed miserably." The Wrath of Khan was only Meyer's second movie, so it's difficult to believe that no one could stand up to Meyer, especially Shatner.
"Try telling him what to do. I dare you. Nicky is Nicky. He is larger than life. His persona is much larger than Bill's. Nobody can tell Nicky what to do. Bill could have tried, but he would have failed miserably."Deborah Arakelian
The Wrath of Khan was a great success, and while the script naturally played a large part in that, the actors did as well. The fact that there were no major changes doesn't mean there wouldn't have been had Shatner or Leonard Nimoy not have liked something. Meyer said Nimoy didn't like his cabin on the Enterprise, obviously feeling comfortable enough to mention it to the director. So while Arakelian believed no one could have told Meyer what to do, that's a little on the surprising side, considering who the stars of the movie were. Paramount had a lot invested in this movie, and it couldn't have been made without those actors who yielded a considerable amount of influence.