I've also heard from several of my client talk show hosts who've had Franken on, and they expect him to be awful as a host because they say he's awful as a guest. One of them told me he cut a Franken interview short because it was just tanking. Franken's style is to speak...very...slowly...with a heavy dollop of sarcastic condescension, as if telegraphing the idea that he knows he's talking to morons. That can get laughs in small doses on TV, but with radio, you have to have a personality that people want to invite into their lives for three hours a day, five days a week.
This is something liberals miss because they're trying to copy Rush Limbaugh without actually listening to them. If they listened to him, they'd discover that for the most part, he's upbeat, polite, welcomes liberals who want to argue with him, and keeps a sense of humor. But the liberal image of Limbaugh is based not on listening firsthand, but on reading what other liberals who haven't really heard him say about him. So they assume he's an angry, racist firebreather ranting to Cro-Magnons. They figure, "How hard can it be to beat that?" Well, they're about to find out.
For me, watching these liberals put together their "radio empire" makes me feel the way a professional plumber must feel watching the Three Stooges trying to fix a leaky pipe. My prediction is that almost all of Franken's callers will be conservatives wanting to argue with him (because that's mostly who listens to talk radio) and challenge him on the issues. They'll be better informed than he is, and with his inflated ego, he will handle this about as well as Howard Dean would and quickly resort to snide namecalling. The stations will mostly be dogs, the ratings will be miniscule, and Al will decide to "pursue other opportunities" within three to six months, perhaps opening a bed and breakfast with Mario Cuomo and Jim Hightower.