Again, I'm not a draftnik, and apart from Michigan, I don't watch any college basketball other before March Madness, but for what it's worth, his BPM in college is relatively pedestrian (this is the same BPM as we have in the NBA).
BPM is only available since 2010 since college pace stats weren't kept before then, but
Anthony Davis had the best BPM season recorded in that time period. Among freshmen, Davis and Towns were head and shoulders ahead of Embiid, who in turn is a good distance ahead of #4 (Zeller). Overall, you look at that list, and it's a pretty impressive group, and doesn't seem far off from the conventional wisdom about best college seasons. BPM isn't everything, but
Bagley currently ranks 156th on that list (if you include this year), with a BPM less than half of Davis's.
This isn't to say he's not gonna be a superstar as a pro, and as I've said, I haven't seen him play a single minute, but he's so far behind guys like Davis and Towns in BPM that it at least raises an eyebrow to say he's the best college player since Durant.