I disagree with him beign overrated. He's a monster in almost every aspect, he's fast, strong, good in the air, a pretty good tackler, etc. The worst thing about him are his MENT and his TW, both are pretty terrible. He's an spectacular tackler, but usually leaves huge holes behind him in the last line when he gets out trying to tackle. Probably his TW could be even lower, in pair with Ramos. He compensates this with his amazing speed, that's why we see so many runs by him.
Anyway I still don't get why his RES is so low, I think he could probably have a better value there, but maybe the mid yellow RES+87 DEF would make him too good overall.
Also I have some doubts on his passing, I really don't know if he's that much better than Sakho, for example, specially at long passing.
Edit: I also don't know if his HEA is so good. He's a monster in the air, but most of it thanks to his JUMP, and I don't see how his HEA is four points better than Pepe. I'd go for an 82 here.