I'm not entirely certain a new Muppet show would hold up right now. Look at what the networks are doing: NBC, ABC, and FOX have all re-arranged their schedules so many times you could get a headache. It's causing a lot of great shows to be canceled, or ratings end up dropping drastically. For a while, I thought Scrubs had been totally canceled. The only station that hasn't really done that too much (other than cable stations) is CBS. They did it once, and I think they realized their mistake.
I'm not certain the Muppets could hold up to the reshuffling. For now, I'd say stick to the TV movies, and when people begin accepting them through those again, re-introduce them to a television series.