If they end up doing a new show, are they completely married to the variety show format? Why retread what they've already done -- why not do a Columbo or Magnum PI type of show, where Kermit is a private eye and Piggy is his secretary, and Fozzie and Gonzo are his goofy assistants... Or the show is in Vegas, and Kermit is the detective, and Fozzie is a lousy local comedian, Piggy is a showgirl... Of course they wouldn't play it completely straight. Lots of winking at the audience. They would realize they were in a TV show. But you could throw just about every Muppet in there at one time or another...
I really don't think the variety show format has much chance of surviving without cramming it full of crass, lowbrow humor. Otherwise it's going to be marginalized as a children's show, and I think we'd all like to see something a little different.
Of course, if a variety show is what they come up with, heck, I'd give it a look-see.