Hey, Edgar Bergen made it big on radio.
Oh, let Condescending Robot and the others say whatever they want. Just think of them as this thread’s Walters. Ironic, ain’t it? 
I enjoy the byplay between Jeff and Peanut (and the other characters)
Watch about the first 3:30 of this clip as Jeff gets madder and madder at Peanut.
Or this one (starts at 3:57) with Peanut and Jose.
There is some excellent comic timing in those clips.
I don’t see that at all. I agree with your assessment of Carlos Mencia, but Dunham actually tries to have good delivery and timing, and uses a lot of slapstick and other physical humor. If anything, he’s a bit corny, like most ventriloquists are.
I don’t like all of his stuff, and I rarely laugh out loud at what he says, but his humor at least rises to sitcom level (well, before I discovered Community).