IMO the main reason why Wenger put Bendtner on wings is becouse when Bendtner is put at the center forward position he doesn't hold the position (not like Chamakh he do it much better)he move deeper on the pitch and on the wings there he gets the ball and tries to dribble past players and then he lose the ball.Imo thats the reason why Wenger see him as a winger not center forward!