Overrated: anyone who plays in the EPL.
Not that I don't like the EPL, or that it is not an extremely strong league, maybe even the strongest. But, the degree to which most people in football tend to overhype it is quite obscene.
For example, for anyone who watches both La Liga and EPL, the fact that players like Mata, Silva, Cazorla, Torres (in his day) Aguero, Yaya etc were good was well established. But even specialized people (like transfermarkt.de) seemed to be surprised when these said players hailing from La Liga, carried over their success (in some cases enhanced it) to the EPL, and massively bumped up their values after a few months of presence in the EPL. If you don't believe me, just check the website which has the function of evaluating the players through time. In short, if you score 10 goals and 10 assists with Valencia in La Liga you are 25m. If the next year you move to the EPL and do exactly the same, you are suddenly worth 40m.