Craig doesn't deserve what he got
This is a terribly sad movie. Craig is royally screwed over and is forced to live as an observer and forced to witness Maxine and Lotte happy while he is stuck in a hellish nightmare. It is terribly sad and her certainly doesn't deserve what he got.
Let's look at it this way: everyone had a happy ending except Craig. Maxine even got a happy ending, and she is arguably the villain of the movie along with Dr. Lester. These are terrible people, but they got happy endings.
why was Craig screwed? He didn't deserve what he got. Granted he did take control of Malkovich for 8 months, but that is no less awful than what Dr. Lester does.
Honestly, it is the saddest movie I have ever seen. And this is just talking about Craig. Malkovich at least gets to expire when his body dies, but Craig is stuck forever until the vessel dies before taking over the next one (who knows how long that will be).