Looking at that list... I wouldn't count the three from 2010/2011 because it's too early to tell, so that leaves 12 players. Of those 12, I would say there are 2 superstars (Bailey, Johnson), 2 great players (Rodgers-Cromartie, Routt), a #1 wideout and potential emerging star (Heyward-Bey), and 3 players with promising early careers that were derailed by injury/death (Mathis, Washington, Williams).
That's a pretty fantastic hit rate, especially given how rare it is for any draft pick to work out. Similarly, if Google tries a bunch of projects of which only 10% are expected to work, but 20% of them end up working, then they still did a great job even though 80% of their projects are failures.