Donald Driver was a world class high jumper, not a pure speed guy. The high jump is about explosion and body control - physical skills that probably help more when you play WR. That body control helps with route running. MVS is a pure speed guy. I think his route running is suspect. The speed thing is a big help, but I'm not sure he'll ever be a top level WR. He can be a useful piece in the offense, but I'm not sure you can count on him to move the chains or be a consistent contributor for 40-50 snaps per game.
Lazard is an interesting guy, but again, let's see. He seems like he can move the chains, but once he's the #2 and getting more attention, we'll see if his size is enough. To me he seems more like a #3 type guy. I hope I'm wrong.