Every moderator is biased to certain degree so trying to find unbiased one to moderate debate is pointless. Instead they should bring one with obvious conservative bias (Hannity/Gutfeld) and one with obvious liberal bias (Maddow/Cooper).
This way both sides will be challenged every time they want to avoid to answer a question.
This idea was suggested on Rush's radio show yesterday (Mark Steyn), almost word-for-word.