Looking at McGinn's collection of scout's comments it just looks like the typical mixed bag of positives and negatives you'd expect for any guy drafted at the tail end of the 1st round. He looks like an incredible athlete who's athleticism still doesn't translate 100% on the field. I don't see that has a bad thing.
In terms of scouting reports, who knows. You provided the Richard Sherman example which is a great example of scouts being wrong. Here is another example of that from Bob McGinn's 2012 draft report:
Third-year junior. "Pure cover corner with great ball skills," Philadelphia GM Howie Roseman said. "They're so hard to find." Went to LSU as a WR but moved to CB in 2009, serving as a deep reserve, before teaming with Patrick Peterson in 2010 and then Tyrann Mathieu in '11. "The only thing that would stop him from being great is that he doesn't have a special catch-up gear," one scout said. "In terms of smoothness, athleticism, ball skills, hands, anticipation - he's really good." Started 26 of 33 games, finishing with 11 interceptions and 12 PBUs (passes broken up). Scored just four on the 12-minute, 50-question Wonderlic intelligence test but scouts say he has a reading disability and learns well in other settings. "He can pick it up," another scout said. "Great kid. Can't read very well. He doesn't take timed tests." Peterson, who had a superb rookie season for Arizona, scored nine the year before. Hails from Shreveport, La. "When I think of guys like Deion Sanders and Charles Woodson and Chris McAlister and Champ Bailey, those guys were a league above this guy," a third scout said. "He's not Patrick Peterson, either. He ends up on the ground some, and I've always been afraid of corners that fell out in space for no reason. But he's a solid cornerback in the NFL.
That's Morris Claiborne.