I'd be very suprised if Niang were drafted. He isn't fast or strong enough to compete night in and night out with the 4's in the NBA. He has a pretty weak vertical and he's prone to getting pushed around and out-muscled for rebounds. He makes up for his lack of athleticism with great footwork and he's a pretty damn good shooter. The problem is that 4's and 5's in the NBA have the ability to recover defensively even if he uses his footwork to get a good look. Plus 4's in the league will be able to cover him on the perimeter.
Niang actually reminds me of a shorter, less athletic Tim Duncan. Which seems like a great compliment. However, what makes Tim Duncan so great is the fact he has that skill set in a 6'11 body. Niang is only 6'7. That 5 inches in height and wingspan is a huge difference. It gives Duncan the space he needs to get his shots off. It gives Duncan an advantage when grabbing rebounds. It gives Duncan an advantage on the defensive end. Niang would struggle mightily with all of those things at that level. Which is why I think he'll end up having a nice career for himself in Europe.