I think it's Wichita State and McBuckets.
In terms of Wichita State, they have some good out of conference wins and they haven't lost. We are not talking about a Calipari Memphis team loaded with future lottery picks playing in Conference USA. Cleanthony Early is, maybe, a first round pick, but he'd be in the bottom half. As many pundits have said, there is a HUGE drop off from no losses to one loss. Perfection is elusive and should be celebrated until the run ends.
As for Doug McDermott, he's going to finish out as one of 7 players in NCAA history with 3,000 points, should finish, at worst, 7th on the all-time scoring list, and will be a first team All American for three years in a row. That's huge. Not to immediately throw cold water on the NCAA all time scoring list, but it is really a random collection at the top - Hall of Famers and guys who never really had outstanding pro careers. I didn't realize Lionel "L Train" Simmons scored 3,200+ points and is 3rd all time!