Dez game was never route running. Dez wasn't fast but he was explosive for his size.
He was a big physical jump ball type, with great run after catch skills. Dez play became an issue after Garrett wanted to shorten everything up, in an effort to help Dak.
But Dez was a guy that had to get some momentum going before he could juke his defender. All of the short, quick cut routes that Garrett and Co wanted Dez to run didn't fit Dez's strong suit.
Lamb is not fast but he is quick. He gets in and out of his cuts quick. And his change of direction for his size is phenomenal. And when you add in his ability to contort his body to make catches, he becomes great.
The difference between the two will be longevity. I believe Lambs natural playing style will lead him to have a longer and thusly more productive career than Dez's. Dez played like Marion "The Barbarian" at WR. And that's what make him such a threat in the redzone. So Lamb is nothing like Dez...he's more like Jerry Rice to me.