I don't think he's there just to be a comedy act, although the man is versatile enough to incorporate some funny stuff once in a while. I think his re-hiring is a coda to his career as an active performer; a last run in the ring that will probably lead to a backstage position with the company. There's no telling whether he has the mind for a front office job, but he could (and has) worked as a trainer.
In the meantime, it's pleasing to see how trim he looks, even in that stupid gold & black outfit, and how well he can still move around the ring. He may be there chiefly to put over younger talent, and a guy with his past fame could be a nice steppingstone for young performers on their way up.
Finally, Dustin is there to help Cody, who's never been able to attain top status by himself, despite numerous programs being written for him. Perhaps Goldust can aid the process, either by teaming with Cody..... or turning against him and working a brother vs. brother feud.
Either way, I'm glad Dustin is back. There's a place for him.
Of course, all this presumes he is really back, and the whole PPV deal wasn't just a way to get Cody his job back.