The mistake there was not so much picking a player who became a bust. The mistake was trading up and picking for need instead of for best player available. People were surprised when they picked Will Smith when they already had Charles Grant and Darren Howard. People were surprised when they picked Deuce McAllister when they already had Ricky Williams. Pick the best player available. If you're duplicating a strength on your team, make a trade and/or save some cap money.
Looked at as a whole, that was probably the worst draft in the history of the Saints.