Wouldn't say he was our most dangerous. He was ok. Thing is, when playing down the left, he often needs to cut back onto his right, which often slows down the move.
Defensively, he was caught out quite often, especially in the second half. Looked like he didn't know when to press, drop, etc. Rose coming on really solidified it.
Next year, I can imagine he will continue to play a pivotal part in the season, though.
Mourinho suggested he would play around 50 games next season, which to me is a bit worrying, as it could mean Jose not bringing in a left back. It could also mean that we buy a left back and rotate Valencia, Young and Left Back, as Young can play both flanks - similar to what City did with Walker, Delph and Danilo.