I should have made this my post, rather than joking about it earlier.
1.Whether Dean is combative by nature or not is actually a lot harder to judge based on the program, than what the media seems to be saying. The show was quite tightly moderated and all the panelists were expected to be generally respectful of each other's right to speak.
That said, a couple of the other regular panelists on the program were right wing extremists (the Editor of the American Spectator) and Canadian economics reporter/columnist Diane Francis, and he always seemed good natured in listening to their wing nut ideas.
2.I thought Dean's views were very much in the mainstream (though maybe that's just me as a Canadian, a somewhat more left leaning country than the U.S). It was obvious he is very bright and knowledgable on a wide range of issues.
3.Part of the time when the program was on, I was somewhat psychotic (around 1999), and prone to conspiracy theories (I take effective medication now). From remembering back then, it's clear that Dean isn't interested in any sort of conspiracy theories or 'alternate' possibilities, out of the mainstream.
Not only would he find the idea that the President Bush was warned of September 11 in advance ridiculous, he would likely dismiss any conspiratorial idea out of hand.
4.For the time I wasn't psychotic (1997-98), the times I saw the program, as I said, he was very much mainstream. A lot of the time he seemed to be summarizing mainstream columnists on a lot of topics.
Overall opinion
Mainstream with no whacked out ideas, or unconventional thoughts and no overarching philosophy other than "what works" is how I would sum him up.