He was a pioneer. He begat the definition of a great heavyweight and despite how we might today perceive him as some crazy brawling lout, the description couldn't be further from the truth. For those who take the time to read up on him, well they could only be impressed. Pollack's book on him is a gem.
I'm actually looking to get Pollack's book on him. I'm half way through the Fitz book and I think it is amazing, probably the most well researched book I've read
IMO Sullivan was good for boxing he was the first gloved champion with 38 wins and one loss, elected to the HOF in 1990 i dont know to much about him i wanna find a good book about him to learn more
Joking aside, Sullivan was a drunken racist lout, but he was also a far more complex character than most boxing fans think.
I'll go with McGrain's compromise answer. He was a great fighter and a racist, drunken lout. Also, just a sidenote: as an Irish-American living in an America that hated the Irish almost as much as it hated African Americans, Sullivan faced a fair amount of racism himself. Depending on your viewpoint, this might make Sullivan's own bigotry more or less understandable. He certainly didn't come from an ethnically "privileged" Anglo-American background like some of the other racist champs did.
Personally, I lean toward 28.3% racist drunken lout, 61.5% great heavyweight champion, and 7.1% guy with an underrated singing voice, with the remaining 3.1% a rounding error. I can see an argument for your point of view, though.
His greatness outstrips his racism/drunkenness, especially when you consider that he lived well over a century ago. Edit: Well, he died less than a century ago, but his title reign was 120 years ago at its end.