They're right. You need a point-of-view character. It's the oldest trick in the book: the double act. If you want your funny guy to be funny, you need to pair him with a straight guy. You can't have two funny guys. For the same reason, pairing the weird eccentric alien Doctor with another alien or a girl from the 13th Century wouldn't work. Me, I like people, I know people, I relate to people. Show me a police procedural where one cop is a ghost and the other cop is a martian and I'm out.