This is the problem with "the eye test." People remember a specific play (say, a missed sack) or a specific game and unconsciously give that more weight than it should get in overall consideration of the player's performance.
A baseball analogy is that Derek Jeter, who was an all-time-great-hitting shortstop and a tremendous athlete, was also pretty bad at turning balls batted to the shortstop's area of responsibility into outs (that's the technical way of saying he was a bad defensive shortstop for most of his career). But because his outstanding athleticism allowed him to make some spectacular plays (throws from "the hole" mostly) that made highlight shows, he was perceived as a good defensive shortstop. Still, if you ever want to make Yankees fans grind their teeth and show PTSD symptoms, just utter the phrase they heard so many times on Yankees broadcasts: "...past a diving Jeter!"
