So Ayton is a defensive liability now? That's a false premise like Doncic is a fat tub of goo is a false premise. Bagley is an extraordinary AD level athlete. He's not likely to be chopped liver on D. He's going to be more agile than 90% of his opponents. It is true he did not play D at Duke. He sat on the outside of a 2-3 zone and rotated out to the perimeter on the three point shooters. Carter was the center of that zone. Bagley guarded a space on the floor and went to the glass went the ball went up. This style of D affected his metrics, including steal and block rate. I am not saying Bagley will be an all defense player with his a 7'0 wingspan and lean frame, but we are talking about superior athlete with fast reaction time. First to the ball wins and he is going to be first to the ball often. This type of athletic profile to go with his motor does not make for a defensive slouch.
Bagley will also most likely have defensive problems. He isnt big enough to play center and alter shots at the rim and only way I see him being effective is that if he becomes a passable switch guy. Even then it creates other problems if he cant play the 5 so there has to be one non shooter on the court with him playing center so it will affect the offense and he is forced to guard quicker wings. With Bagley I have hopes he could become a guy who plays 50/50 4 and 5 and basically just switch everything
Also these guys are bigs so defense will be very important with value as a player. More important than with Doncic or Porter