As for "barely drawing single teams"... no one is going to double someone who doesn't have the ball. The Hornets aren't running a lot of plays for Davis yet, so the ball is rarely in his hands. And maybe you should credit Davis for getting open under the rim or running the floor better than those who are guarding him. Shoot... Davis scored 17 of the team's next 20 points after he got into that altercation with BJ Mullens. That's probably been the most impressive thing he's shown so far.
But if it was as easy as you seem to imply, then more bigs should average 17+ a game, especially as they gain experience. There are plenty of players that "barely draw single teams", yet they can't score at all.
The reality is, Davis is one of the top 5 players to come out since Duncan. The only two players I could see drafted over Davis in that span are LeBron and Oden. And even then, I'm not too sure. LeBron was coming out of high school so it's hard to compare. Also, word out of Portland was that Oden was out of shape at his pre-draft workouts. We also would have likely seen an Oden vs Davis National Championship. If Davis won that matchup, he likely would have went #1.
I'd also dare to say that Davis would have been taken over Duncan if Duncan came out after his freshman year.