I finished the first draft, I've finished the revisions. Now I need to make the play work.
There are two problems with the script:
First, the "gimmick" of the play is that Sonny undergoes these identity shifts at moments of confusion. Something happens, and his Dad tags Sonny out and takes over the scene. Sonny's fiance Luci does not notice the physical change, and continues the scene as if nothing happened. Sonny struggles for control and kicks his Dad out of the acting area. Another moment of confusion occurs and Sonny's Mom takes over, etc. If this remains a "gimmick" and not a driving force in the play, the whole thing is going to suck.
Just as an actor has to fully commit to her choices in order to render a successful performance, so too does a playwright have to fully commit to his choices. You can tell instantly if a choice is arbitrary and tacked on. I don't think we typically look at the actual script in this way, but it's an obvious point of analysis once you do. One of my jobs for the next draft to make sure I've fully committed to this "identity shift" choice and really go for broke with it.
Second, The play dies after the halfway point. The reason is simple: Sonny isn't fighting for anything, he's fighting against his parents. Fighting for is stronger than fighting against. (For instance: In Braveheart, William Wallace fought for Scotland, not against the English. It didn't matter who the invading force was, they were invading his homeland! Compare this to Troy, where Achilles fights against Troy. He has nothing to fight for. There's nothing at stake -- it's boring. The movie picks up after the death of his cousin -- now he has something to fight for.)
Sonny has to fight for his relationship with Luci. The play deals with how all the garbage we carry around with us (in this case, the habits and manners of our parents) can affect the choices we make. Sonny needs to fight through that garbage, not against it.