I don't get why people are saying this is for a younger audience. The Muppets are about bridging the gap between children and adults. They're not supposed to be dumbed down for a stupid tween show.
Of course we fans know that the Muppet Show was created as a prime time program for adults and the Muppets are supposed to be for all audiences.
That said, the marketplace is much different than it was in 1976. Children drive the market now more than ever and not enough of them have the connection with the Muppets that we do. Today's audiences don't often channel surf outside of their own comfort zones either. This means that the Muppets must continue to appear on all sorts of relevant programming, specifically those geared to younger audiences.
However, that does not mean they should be lobotomized and I don't think they have been from the clips I've seen. I think Disney's doing a good job forming and maintaining connections with the Muppets. My only gripe is that they need more Muppet merchandise in stores. More kids like the Muppets, the more products we'll see.
This appearance is a good thing.