I used to media-train people for a living. Russert was relatively nice to Thompson because as you said, Thompson controlled the interview (i.e., it wasn't for lack of trying to savage him). One of the advantages to talking slowly and deliberately, and verbally examining an issue in response to a reporter's question, is that the reporter subsequently has less time to run the interview his way. You'll notice Thompson didn't even let Russert interrupt him -- he kept talking when Russert tried to machine-gun him, and even told Russert "now, let me finish" several times.
Great job by Thompson.
Indeed, Fred is a formidable opponent. Russert appeared as a tousle haired schoolboy in comparison.