I don't think a revert's necessary, but I would like to see something done with him. I used to play him occasionally from time to time before; but whenever I decide to pick him up again, he just feels worse and worse, in the sense of not belonging in this meta.
As long as you have an ability which can kill his voidlings, you basically deleted half of his kit, and if you don't eat everything he throws at you in lane, he won't be able to one shot you until later into the game.
And that's his only saving grace, he is very strong late game, and he can stall/delay the games incredibly good. But the meta revolves around early skirmishes, roams, jungle invades, ganks, cheesing someone early game and etc., Malz just provides very little in terms of damage, utility and roams in the early stages of the game (his silence takes awhile to scale up to a reasonable duration and his ult has a high CD until 11), which is why I think he feels so bad to play right now.