There are different types of "speed", i.e., top-end, quick-start, level, etc.
Dwight and Banks had true track speed, i.e, not just 40-yard dash, or quick-start. Dwight was a Big Ten 100 champ and 200 runner-up.
Bob Sanders and Freddy Russell both had fast 40 times, as did DJK, Shumpert and a few others. Wegher supposedly had good 40 speed, but never looked as fast as (self) advertised. Brodell had track speed, but his feet didn't look "quick" like Powell or Parker. But over 100 or 200 meters, he may have been superior to them.
That said, we seem to have some good speed outside, as well as LBs and DBs that can move. But speed, no matter how great, is negated by things like poor hands, bad route-running, not seeing holes or not playing for proper position.