First off, Doncic isn't playing PG in the NBA EVER... no way, no how. At 6-8, he would have to be some otherworldly kind of athlete to even consider that, and he's not.
Secondly, I am hard pressed to find what anyone sees as so out of this world about him anyway. Yes, he has a decently mature court awareness and maybe above average handle for his age. But what does that really translate into? He shows no particular signs of being an outstanding shooter, rebounder, defender. I highly doubt he will be an especially high volume scorer, especially being defended by mostly superior athletes at the next level. If he does reach his full potential you maybe end up with a guy who at best is an offensively sound one way player, maybe a decent third or fourth option on a good team.
I see his ceiling as being something like a 15 ppg, 5 rpg, 6 apg kind of player. Not bad... assuming he even reaches his full potential. But not something you pass on two potentially all-league talents like Ayton and Bagley for... or even two high ceiling bigs like Bamba and Jackson.
I would be fine with Doncic as a pick if we end up slotted at somewhere like 5 or 6, or maybe even at 4. But as the top choice with some of the other guys on the board this year? It is sheer folly.