Honestly, I'm not that high on him.
The problem with bender is that I see him as the perfect example of the whole "jack of all trades and master of none" analogy.
Bender is good at a lot of things, but I just don't see that one single area where he is elite.
Defensively he can defend perimeter players with his mobility and is a decent shot blocker...but his lack of physical strength and toughness limits him as a one-on-one post defender and there are questions about whether he'll ever be more than just "pretty good" as an overall defender. I don't think he has the defensive upside of somebody like Ingram.
Offensively he can pass and handle the ball - but he isn't really elite at either of those things, merely "solid". He isn't a big man who can handle the ball like a guard (e.g. Magic Johnson) so much as just a pretty good handling/passing big man (e.g. Olynyk).
He isn't a lights out shooter (like Dirk). He isn't even really a good shooter (like Olynyk). He's just a guy who has a half decent jumper and the perceived POTENTIAL to become a good shooter (as Sully was believed to be at draft time).
He's not by any means an outstanding rebounder like say, Sully or Randle. He's merely a decent rebounder, like Marc Gasol or Dirk.
At 7'1" he has pretty good height, but his wingspan (at 7'2") is good rather than outlandish. Likewise he is quite mobile for a man of his size, but he's not an "Anthony Davis" or "Dwight Howard" caliber athlete.
This is the whole thing with Dragan Bender. He doesn't have any real major flaws, but he doesn't have any real major stand-out talents either. The biggest selling point is the fact that he is only 18 years old, and so you hope he can surprise us all and take his game to a whole other level. That's a big risk though. He may well just develop into a pretty good all round player who isn't great at anything.
I think it's very unlikely Bender will be a complete bust. He should (at the very least) be a quality starting center in the NBA for many years. I just question his upside - does he really have the talent to develop into a big star? I'm not so sure.
Ingram and Simmons clearly have that potential.
Simmons is a 6'10" / 240 pound guy who runs/dribbles/passes like an all-star point guard, finishes like an athletic small forward, and rebounds like a power forward. His floor is probably Josh Smith (who was still a fringe all star for many years) and his ceiling is Magic Johnson (an all-time great).
Ingram is a freakishly long, incredibly athletic wing who can shoot, pass, defend and handle the ball. If he can put on some muscle, there is almost no limit to how could become. His floor is probably Tayshaun Prince, and his ceiling is Kevin Durant.
Bender is much harder to pick, because he has such an odd combination of talents and physical attributes. I feel that his floor is a skinnier and more mobile Kelly Olynyk, and his ceiling is maybe Andrea Bargnani but with less scoring ability.
I have more confidence in Hield than Bender, because Hield at least has one area where he is truly dominant (scoring), and also has other complimentary skills where he either is (passing, ball handling) or has potential to become solid (defence). I think his floor is Jamaal Crawford and his ceiling is Damien Lillard .