If stunts are required, a stunt man is a good investment. The actor's role in the cinema is different from the actor's role in the theatre. Most actors are quick and responsive, but they cannot give what they have not got. I do not like the God figure on set. They are people who generate a terribly bad feeling on the floor and this can wreck their films because nobody, but nobody, is going to have the slightest interest in what they want.
Stage actors have to tone down their performance because the cinema deals in close-ups.
Stage actors sometimes have a tendency to project too much and try to do too much when they are in front of the camera. This is the main difference between the two media. In the theatre you are projecting, and in the cinema you are thinking. If you think clearly enough, you can communicate with the camera and of course, there is a difference in the amount you have to give in an extreme close-up and the amount you have to give in an extreme long shot. The actor must look and sound sincere.