It would be hilarious if he made like a deathbed confession of all his BS. It would be horrible though if he actually had a successor chosen to take over his show.
Nobody is going to take over his show, nobody can take over his show. Like Oprah, he's spent decades cultivating and catering an audience that is firmly within his thrall, and isn't really interested in anybody else.
There isn't any other political commentator, radio, TV, or otherwise that can even touch Limbaugh as for the size of his audience. And there's a lot of people out there that would love a piece of his pie, but I'm just guessing that for any dittohead out there, while they might be ideologically aligned with any number of other conservative pundits, just simply wouldn't be as politically involved (if being one of Rush's boys counts as that) if he went away.