Actually, of all people, Huckabee had a good method in 2012. He had a full program ‘talking’ with each candidate in turn. That gave them a forum to discuss their policies and ideas without interruption or gotchas or a minute to respond.
IIRC, Huckabee also had a stipulation that you could not refer to any other candidate. Such a format is a good way to find out what each candidate stands for on the issues, instead of having the “debate” turn into Jerry Springer.