The first rounder in 2013 got traded down,, which led to EJ PLUS Kiko in the second round with the extra pick. Kiko got traded for McCoy. So out of the 2013, 2014, and 2015 first round picks the Bills got EJ, McCoy, and Watkins.
In my opinion the jury is still out on EJ. I suppose you could say it's also out on how the other two will work out, but I don't think on the face of it this was a bad outcome.