If we're talking purely about what they do on the pitch, then he has to have been one of the most overrated players in the world before we signed him. He had 1 productive season and was always pretty good, but nowhere near one of the best in the league. Incredibly reliant on system and players around him, he has the body and physicality of a child, and isn't even that creative on the ball. He just has a good first touch and is safe with his passing. He should be one of the first to be sold this summer, literally never provides anything and whenever he plays, the right wing is entirely pointless.
Overall he was an OK signing but massively overpriced at the time. Had good moments under LvG for us, especially at Anfield, but one of the most pointless players under Mourinho (as was expected tbf).