It doesn't look bad. The Bills needed a major OL upgrade and Mike Williams has been a solid starter, if overpaid. That is indeed the price you pay for having a top 5 draft pick.
Just looking at the first round from 2002, who would you have rather had? Dwight Freeney, as mentioned above, clearly would've been a better choice. That draft really wasn't overly impressive, in hindsight, and kind of underscores why having a top five draft pick sucks in this day and age. Unless the guy comes in immediately and plays like an All Pro, his salary is so high that if he needs time to develop, he's going to be viewed as a bust, at least by some.