This whole Lamela thing is classic knee jerk reactionism, its the nature of football fans these days. Your only as good as your last performance, nobody looks at ability anymore, which Lamela obviously has in abundance, he's played two very good seasons in Italy. Lamela is being played out of position, in a role that doesn't suit him, and under a manager who killed his confidence. He's 21-22 years old, so its natural that he doesn't have the maturity to deal with such a situation. Admittedly he isn't a hard worker, he's not the type of player that will track back and help out defensively, he also isn't the kind of player who is effective playing so far away from the opposition goal, he's deadly in the final third, I think he's like Messi in that regard. Imagine if Messi was playing in Tottenham, and they put him on the left or right wing in a 4-4-2 and asked him to track back all the time.
Theres no comparison between him and between average players like Townsend, Lennon and Chadli, they definitely fit Tottenham's system more though.