He's not going to be good. Guys who don't produce in college (which he did not) most certainly do not produce on the pro level.
His ceiling is Steimsma. He'll probably have a similar career path to Sean Williams.
The NBA all time leader in blocks per game only was able to get on the court for 300 minutes for his college team in two seasons. There certainly are precedents for specialists like shot blockers to flourish the NBA despite skimpy college production.
I don't know how posters can look at a guy for 40 minutes of playing time and make all these grand pronouncements either way. - Melo's going to be good or Melo won't even be able to do this or that.
I look at a young big man and try to figure out if he has the size and tools to be an NBA player. How he actually plays in his third summer league doesn't weigh too much in my evaluation. I look to see how competitive he is, and how hard he's playing.
On all these counts, Melo looks good.
Regarding Melo's hands, a couple of times in yesterday, he was thrown passes that are very difficult for most 7 footers to handle. One he scooped up flawlessly, but the one Sully threw him he couldn't handle. To be fair, he would have needed a first baseman's glove for it.
He's shown court awareness with a couple of deft touch passes. He's shown that he can get across the lane and block and contest shots from guys that he isn't covering. He bodied up Plumlee as a low post defender a couple of times. These are all good signs.