Well, at least people are consistent. Tavon Wilson was a bad pick because the media predicted he'd go in the sixth, and Alfonzo Dennard is a great pick because he was mocked to go in the first.
And there are comparisons to Darrelle Revis as a press corner.
It was not too long ago that Ernest Shazor, a physical first-team Big 10 and All-American safety who was projected as a first round grade by the majority of scouting publications, went completely undrafted. Downfall? Combine 40 time was too slow. Could keep up with college receivers enough so that his toughness and instincts could come into play. Did not project to the NFL at all.
The difference between a college press corner and an NFL press corner is immense. NFL receivers are more mature and better at getting off the line, and faster getting by you when they do. Darrelle Revis was the first corner off the board in 2007 because he was a 6' press corner with 4.37 speed at the combine. That is bona fide NFL recovery speed. He can lose the battle at the line and still stay with a wide receiver in man coverage.
Alfonzo Dennard ran a 4.55 official combine time, and the lowest I've seen is 4.51 with a stopwatch. He is also 5' 10", not 6'. He does not have recovery speed. He is going to have to be very good at jamming people, otherwise he's looking at a possible move to safety. Maybe he's a Chad Scott red-zone corner but, again, Chad Scott was tall at 6'1".
People have talked about Dennard's struggles at the Senior Bowl in Cover 2. Cover 2 can be played a few different ways, but the standard way is to have the corner sit at five yards and jam the outside shoulder of the wide receiver in space at that location, to (1) knock him off his timing route if its a quick one, like a slant or hitch or such and (2) keep him from getting a free outside release on the Cover 2 safety. Dennard apparently struggled jamming in space against elitle college players.
I think his struggles jamming in space at the Senior Bowl, plus his slow 40 times, are more important in explaining his fall than his noted pugilistic instincts. They paint the picture of a great college player whose game is very dangerous at the NFL level. He's probably not going to get any faster, so the Pats had better hope he can learn to be physical in space, otherwise he doesn't really have a place on the football field.