I'm not disappointed with the Allen pick at 21, per se. If the Jazz didn't want to draft Okobo, or Hutchison, or Robert Williams, then they have their reasons. They obviously scouted the **** out of Allen, and they wanted to draft him at #21. They weren't interested in trading back and picking up an asset.
If I'm disappointed, it's that the Jazz weren't able to move up into the teens to get someone with more upside, like Lonnie Walker, Troy Brown or Josh Okogie. All three of those guys have more upside longer term than Allen and could be legitimate starters in the league.
Grayson Allen will be good at what he does. He'll be a reliable 3-pt shooter. He'll play his *** off on defense. He'll handle and run the plays that Quin wants to run without conflicting with Donovan Mitchell. He'll be a good rotation player, and may be a piece of the puzzle. If he gets hot shooting the ball during a playoff series, he could make a difference to winning the series.
DL says that Allen has been a complementary player supporting the star players at Duke, and that's the role he'll have here. He's obviously well coached and is as NBA ready as anyone we were looking at.