Don't forget about how important the O-line performance is for WR's, especially ones with speed that you want to get down the field. If your QB can't find time to look down the field and check his progressions, then even if your WR's are doing an excellent job of getting open, the QB won't have time to find them, and the ball will either wind up in the hands of a RB or TE on a checkdown because that's the only guy the QB has time to find.