I would fear KU if I were an opposing team because if they are hot from three, you can't beat them. KU has shown that they can hit 15+ threes in a game. If they do that, you're probably sunk, regardless of how well you play offensively because you're most likely trading threes for twos. So I agree that KU is a nightmare matchup in that respect. You don't want to catch them on their one hot night, because your season is probably over.
On the opposite side, though, as a KU fan, I worry about that one cold night. As KU fans, we aren't worrying about just one game. We have to worry about each step along the journey. That's what makes it harder. KU will almost certainly shoot someone out of this tournament before everything is said and done. But they likely won't win it, because they will probably have one cold game that ends their season.
Same reason as an opponent, I would worry about playing Arizona with Ayton (what do you do if he goes for 30 and 18?), Alabama and Sexton, or Mizzou with a healthy Porter. Those teams likely won't win it because they have flaws, but their one lottery pick could carry them on a given night to end your season. But if I were a fan of those teams, I would worry that the ride will be short because I can't imagine those guys carrying a team past the Sweet 16.
Remember how KU just dismantled Purdue last year in the Sweet 16? How great they looked? I certainly do. But I also remember what happened two days later. That cold shooting night is lurking. If KU can keep it at bay (and get some good slashing games from Newman) they might be able to survive it this year. But it is lurking.