And if the Cowboys get a speedy deep threat, can Dak get him the ball? Can the line protect Dak long enough for the receiver to get deep? Will there be enough plays for a deep threat after Zeke gets the ball 30 times a game, Dez gets his throws, Beasley gets his, Witten gets a couple because he's the only one open and Dak runs a couple of times?
I think the blazing fast receiver is a bit overrated these days, what with the proliferation of the West Coast offense and these big, fast DEs that put lots of pressure on the quarterback.
Who was the Eagle's blazing fast receiver the year before, or the Patriots' blazing fast receiver the year before that? Not a requirement to have that kind of a guy these days, and it's a huge risk taking one early in the draft, lots and lots of "sure fire" deep threat receivers that have been busts over the years.
Not to say you should totally ignore them, depends on who is available in the draft when you pick...