Its funny that nobody can think of a single person that thought Urlacher "slow" before the epic "they are who we thought they were" game. Except you.
I will say in all fairness, I have two specific memories about people dismissing Urlacher and I believe they both happened pre-Superbowl. I remember a SI article about how Urlacher was the most overrated player in the league around that time, and while not blaming him for being slow, it is still dismissive of Urlacher's greatness.
My second memory is more specific but I don't remember who said it; but there was a poster on the old cbmb that said our defense would do better with Hillenmeyer while Urlacher was out, and Urlacher would be expendable for a trade the next season. I only remember the claim that Urlacher slowed down because I went on a hyperbolic rant about how bad Hillenmeyer was solely because he had previously been a Packer.
Now I would like to take a moment to remember how great Urlacher was at taking the best angle and beating backs (and Michael Vick) to the sidelines on outside runs. Man alive, pair '06 Urlacher with R. Smith now and I don't think we'd surrender a run more than 5 yards all year.