Bagley does not have the defensive potential of a AD/KAT. For example, Tatum, MPJ, and Bagley are all in the same realm length wise, wingspan and standing reach, while AD (7'5.5'' wingspan and 9' standing reach) and Towns (9'5'' standing reach and 7'3'' wingspan) posses elite length for the 4/5 with great basketball abilities...obv length is just another variable and if a guy can play then he can play.
Bagley does have great offensive versatility and should be very good offensively.
We are lucky with Tatum and possibly are underrating him compared to MPJ bc they both have almost the same wingspan and standing reach.