What I always liked about villain Stefano was how he came on for a year or so, caused considerable problems, but then was gone, 6 mos, a year or so, and bingo, he was back.
However, the last several years, he has been in Salem continually, rather a watered down version, but that was o.k. (LOVE joe Mascolo).
They tried banishing him from town, keeping him in Europe, phone conversations, etc. But while he seems to know everything that goes on.....he truly has not caused any problems himself, except for trying to kill Marlena by having her thrown out that window.
It just is very unusual for Stefano to not have any dialogue throughout an entire show, two shows. If he is passing the mantle, would have liked to see some talking between him & Andre', instead of Andre' taking over the entire conversation with whomever comes to visit.
There has been no explanation on the show........or anywhere in the media.....at least so far.