As ever, question of perspective.
Nothing in the series has ever implied he's the strongest character. So if people are saying that- which I don't think is actually a very popular opinion at all, certainly not here at any rate- then yeah, he's overhyped.
Howerver, I would say on the whole (again, based on this site, I don't really care about what anywhere else says) he's actually started to become quite underrated. Something I never thought would happen to him, tbh. Mostly due to the strange political machinations of the various factions of fanboys.
The case of Shanks vs Mihawk is a particularly curious and self defeating one where both fanboys spemd all their time trying to make the other seem like fodder trash. Which is incredibly self-defeating considering the links between the two. It would actually make more sense to wank both to high heavens as a super rivalry like Roger and Whitebeard.