Malzahar - is he really strong ? Or just an U indicative winrate?

http://champion.gg/champion/Malzahar/Middle

I personally really liked malzahar's rework and found it to hit its mark in making malzahar healthier and more unique.

It seems though that he is overpowered given his recurring appearance in the lcs and his overwhelming winrate of ~55% as a mid laner.

So what is it that is broken in mid lane malzahar? Well if anything his total damage output went down across the board in the early game. While he scaling is now drawn out to more dps focused with the voidflings rather than the old burstier kit. All he really got was his new passive, which basically makes him safer in lane and more consistent late game while channeling.

So what is it that makes him so overpowered ?

Also can someone explain how is it that malzahar players with 50-125 games played have a ridiculously high winrate, while players with 125+ games have a much much lower winrate??? Do they like get dumber as they play him more or what ?