http://aol.sportingnews.com/ncaa-basketball/story/2012-04-25/ncaa-tournament-all-time-champions-no-3-kansas-of-2008
The virtual certainty that teams #10 and #6 would blow the #3 team off the court by at least 20 points aside, the article used for support of that pick contains the following:
"the Jayhawks never held the No. 1 ranking that season"
so in a down year in college basketball, it was never considered the best team in that particular season.
"upsets at the Alamodome came over North Carolina, with Tyler Hansbrough, and Memphis, with Derrick Rose"
Its only two quality wins of the entire season were both considered upsets.
"If that ball had not gone in, we probably wouldn’t be in same position. I probably wouldn’t have gotten the raise that I got.”
Its success was predicated on a single fluke play.
"Memphis coach John Calipari had to be asking himself afterward: Why don’t we do the little things as well as they do?"
And they only won a title due to an epic meltdown of the opposition.
The article also details the path to the Final Four to be against a 16, 8, 12, and 10 seed with them nearly losing to the 10 seed.
Not saying it wasn't a valid and notable accomplishment (unless you consider it was achieved on major probation and with two ineligible players and a litany of shadiness), but putting that team among the top 10 champions of the 64 team era seems a pretty big stretch. #3 seems indefensable, and the article they wrote for support seems to almost be more refuting that position that supporting it.