I never mentioned anything about Valencia on the left flank
Dude you have got that wrong 100%, before his injury he was first choice on the right wing two seasons ago when he injured - at that time Nani was playing on the left. It was when Valencia got injured that he (Nani) spent more time on the right. Remember Valencia has had a number of injuries.
The bottom line though is that be it nani or Valencia Man Utd have a high quality player on the right and I would contest that one is backup for the other.
Now lets cut to the chase, Spurs play a formation whereby our wingers are paramount, that being the case we need options in those positions, especially in the case of Lennon who picks up an alarming number of niggling injuries. We cannot afford to be a club that continues to suffer once Lennon gets injured. I do not mind if we sign a top quality right winger or a player with obvious potential but we need to do one or the other.
My concern was that we play our best football with two natural wingers and that was one thing he was not. He could not do a Sandro/Parker job either. I only remember him playing well against Milan, but that was a game when all our players excelled.
I hate it when managers buy a player because they think he is good but have no idea as to how he will fit in the team jigsaw