You can be a deep threat and run in the 4.5s. Having elite speed absolutely helps in this department; however, how many of the uber fast speed guys end up having storied exceptional WR careers? A lot of them become one trick ponies who contribute occasionally and probably provide some help at KR/PR. What you want is a WR who can get clean releases, and can stack a cornerback. That, I would say is the most important aspect of getting deep. This is how Gallup was doing it before injury.