Kessler is necessary but not sufficient to make him HOF-worthy. He needs to beat Kessler and then beat one out of Winky, B-Hop and Taylor to really have a claim at it. If he goes out w/o fighting one of those three, I think it's pretty unforgivable. (though I suppose I could forgive him if he took huge $$ for an RJJ fight, though it wouldn't advance Joe's legacy an inch since RJJ is definitively at least 5 years past it)