The thing is, Hope did shoot Stefano, several times, he was dead, she covered it all up with the help of Rafe. All of that, at the time, was a crime. Guess the writers had to find a way to exonerate her, so she could go walking around Salem, be commissioner, etc. , thus Shane & Steve dreamt up the "plan".
Yep, Andre found him, took the ring, etc. etc. And we probably are supposed to believe that perhaps Rolf somehow brought him back to life, blah, blah. The fact remains, Joe Mascolo has passed away, and absolutely NO one can be recast as the character, Joe owned that character. So, Stefano is not going to appear, except in that portrait we see still hanging in the DiMera mansion.
And while Hope is free as a bird, she did the crime and won't serve a day for the it.
Rafe aided and abetted, he, too, thinks Stefano lives, and the 2 people who know better are no longer in Salem. Convenient, huh?