I think the flaw is that he's limited offensively at this level.
He isn't creative. His shot isn't high end, by NHL standards. He's certainly fast, but his overall mobility outside of straight line speed isn't terrific. His passing skills are rather meh. Finally, I think he suffers from tunnel vision. He gets the puck on his stick and he wants to get it on net, even if it means leaving his linemates behind with his speed, or putting a bad angle shot on net.
Etem is a player who, I think, would be much more successful if he reinvented himself like Cogliano. He was also expected to be an offensive contributor, and he even was for a bit, but it wasn't something he could sustain. When we acquired him, his role wasn't that of a top six scoring forward, like he was in Edmonton, but a utility defensive forward. And it's difficult to argue that he has been much more effective in that role. For us, at least. That's what I think Etem needs to do.