People who cite his speed as a negative really don't know what they're talking about. It's the same absurd talk that we heard last year about Michael Crabtree. And just like last year, it's completely wrong. The fact that Calvin Johnson and Andre Johnson are tall, heavy, and fast has seemingly lead some people to the erroneous conclusion that every single elite WR prospect must be tall, heavy, and fast. People who think speed is the sole determinant of upside for WRs don't really understand football and how the game is played.
Here's the golden rule with speed: if you're slow, you'd better be big. If you're small, you'd better be fast. Little receivers like DeSean Jackson and Steve Smith need to have great speed and quickness because it's the only way that they can consistently get open against 190 pound corners with 4.4 speed. Big receivers don't need elite speed and quickness because they can outmuscle and overpower defenders. The people who said Crabtree was too slow to succeed in the NFL completely missed the point. Speed was never an important part of his game. He made a living with initial quickness, a big frame, great hands, and phenomenal football instincts. His game was never about burning people downfield, so why did he need elite speed?
He didn't.
Now let's talk about Dez. The first thing you need to realize is that he's huge for a WR. At 6'1" 224 pounds, he's one of the bulkiest WRs in the league in terms of BMI/body thickness. Here's how he compares to other jumbo WRs:
Andre Johnson - 29.5
Dez Bryant - 29.1
Anquan Boldin - 28.9
Larry Fitzgerald - 28.3
Calvin Johnson - 28.3
Michael Crabtree - 28.1
Brandon Marshall - 27.6
Calvin Johnson has elite built up speed and Andre Johnson is a freak of nature to run as fast as he does at his size, but as a whole the above group of elite receivers are not defined by their speed. Fitzgerald and Marshall are high 4.4-low 4.5 types. Boldin and Crabtree are probably a little bit slower than that. They're still wildly effective because they have a great combination of quickness, strength, height, hands, and football instincts. That pretty much describes Dez Bryant. He's bigger than Fitzgerald/Boldin/Crabtree and he has a comparable combination of athletic ability and football talent.
Let's take a closer look at his workout:
6'1.5" 224
40 - 4.52 seconds
Vertical - 38"
Broad Jump - 11'1"
4.52 is not bad speed. It's about on par with Fitzgerald, Edwards, and Marshall. If those guys can make big plays with this speed then Dez will too. He has a nice stride and you can see him pull away from people on some of his punt returns. No, he won't be burning everyone at the NFL level, but he will run step-for-step with most corners and is fast enough to sneak downfield several times a game.
38" is a very good vertical leap. It's not quite super elite, but it's pretty close. It would've been a top 10 result among the WRs at the combine.
11'1" is an elite broad jump, particularly for a receiver who's only 6'1". It would have been the best result of any player at the combine and better than any of the other WRs by half a foot. And this comes from a guy who's heavier and thicker than almost every other WR/DB in the draft. So...a guy with a massive frame still blew away the competition in a drill designed to test a player's upfield explosiveness.
This guy is one of the most talented WRs to enter the draft in the past few years. He's a better athlete than Crabtree and Fitzgerald. He may be a better overall athlete than Calvin (he's not as fast in a straight line, but I think he's quicker with better playing strength). He can be as good as he wants to be. If he stays healthy and works hard, he's probably a future Pro Bowler.