Kevin Costner didn't become an Oscar-winning director by being a pushover. He is a notoriously headstrong Hollywood player, and he doesn't have to be directing to exert his influence. There's a great story about Costner butting heads with director Roger Donaldson over a bit of staging while shooting "No Way Out," and how that reignited Gene Hackman's desire for acting. It's not often advisable or appropriate to undercut your director in front of the crew, but sometimes it produces a happy result.

But there's a time and a place, and that time and place is rarely the press tour in support of the movie you should want to be a major hit. The trouble with speaking out this late in the game is that there's nothing to be done; lots of people have a good deal riding on the film's potential success, so inveighing against some shortcoming or perceived...