The whole problem with your premise is that it's only useful in hind-site. Evaluating what the players have become long after the draft. There are too many other factors that come into play (luck, quality of team, internal drive, injuries, etc) to compare the past vs the future.
Maybin was a one hit wonder, who had most of his sacks against weak competition, has a small physical frame, etc. This is a much harder pick to justify than Donte's.
Your rational for saying Whitner was a worse pick because there were higher quality alternatives is like beraiting Michael Jordan's high-school coach for cutting him for some other schlub. This guy picked some loser over the single greatest basketball player ever. I say we set him on fire.
It just makes no sense.