His ego is entirely too big to stay out of the spotlight for good.
I don't care how many times he goes to church.
Lots of people "find God" for a little while...then they're back to their old ways.
This is in no way a guarantee, but it is very possible for Shawn to come back, get hooked, and revert back to some form of the sniveling, spoiled little junkie he always was, playing backstage politics and doing strange shit behind (Vince's) closed doors.
One of his best friends is heir to the throne.
Another will occupy a posh backstage position.
Start, now, the countdown to Hall's return.