Vader was ordered by the Emperor to make sure that the Death Star is operational, by the time the rebel fleet arrives.
He can’t leave. He must obay his master.
He might send some troups though, if he has any at his disposal mind you, since the legions are stationed on the Endor moon, waiting for the rebels.
Plus the Emperor knows that Skywalker will come to Vader, and he tells this to Vader exactly when he needs to. When Vader’s job is done on the Death Star, and has some time to kill before the rebels arrive.
So logically, Vader is not going anywhere.

I see what you are saying, especially in relation to Vader’s character as presented in ROTJ. However it is clear in ESB that Vader is undermining the Emperor and plans to betray him. (The Emperor informs Vader of there new enemy, who Vader has already been searching for.) I would personally do away with most of the “I must obey my master” type dialogue, I see Vader as a slave to the dark side more than to the Emperor himself. If Luke, Vader and Palpatine all have different intentions it makes for greater drama and tension. As well as this, I like the idea of Vader returning to Tatooine is what was meant to be the final chapter.