An impressive roster spot means he's not just making the team he's dressing on Sunday and gets into the game. WR and QB are probably the only 2 positions where you can get a good evaluation of talent in non-contact OTAs.
4.58 40 wide outs rarely get drafted in the first 2 rounds. But if playing wide receiver was all about running from point A to point B in a straight line Usain Bolt would be in the NFL. Not discounting speed - it's critical but a guy like Ridley, with 10" mitts and the ability to make precise cuts, could have a long NFL career.
In 2 years the Bears have gone from a WR depth chart with a bunch of #4s to a depth chart with a bunch of #2s.