A powerful, critically acclaimed director pushes a naive, up-and-coming actor into the realm of psychosis, all for the sake of the character.

From the logline it seems the director is the lead character, the one with the goal and moving the story forwards. If so, why do we want the director to succeed? What is our motivation to like the lead character.

What is the story? What happens and to whom?

This logline describes a situation (a very Kubrick one...) but doesn't describe a main character, flaw and goal.