That Niang goal after the great Ben Arfa pass was the kind of goal I thought he would score a plenty throughout his career, but it just has not happened yet regularly.
He has the speed, strentgh and shot to score those ones, but like Evilo said has just been inconsistent. He has also been played a lot on the wing, which is the wrong choice, imo. He can make it as a central forward, just not as a target man playing his back to the goal, which doesnt bring out his best qualities. He is probably not easy to accommodote to a top team with lots of possession, but in the right circumstances he could score a lot. Kind of like physically smaller version of Romelo Lukaku.