Complaining that Malzahar is too strong is like complaining that water is too dry.
Coming from someone with a /lot/ of practice in him, you have to massively out-think your opponents if they know how to face one.
Otherwise they pop your passive with any number of things and then just insta-kill you.
His ultimate makes him vulnerable to everyone else, like ganks, and does not do anywhere near the damage it did (in fact, they shaved off 40% AP Ratio and 140 base damage when they nerfed it) when it was possible to Flash + R someone. Even then, Flash R only worked if the player was really bad at positioning or monitoring their life. You still had to land E and get your voidlings out unless the player was awful. Otherwise they just flash away as well.
The voidlings are a joke when everyone has AoE damage or can easily just auto them early game to keep him from free farming. His early game is atrocious unless you really focus on the early game, which requires a very specific strategy.
I wish they would make the voidlings more resilient to autos and AoE damage.
Assuming they reduce the absurd mobility and insta-kill champions in the game, he would be fine then.
I really do not want them to rework him because he will be a terribly unfun champion then.