That's not true at all. The voidlings target whoever you target with certain abilities. If Malz ults someone, they gain the highest priority. Then the priority goes to anyone inflicted with Malz's E. Then anything that Malz is currently auto attacking. Then finally just anything that's hostile.
Proper use of your E in lane is key to telling your voidlings when to go ham, or just farm. And there's not really a big issue of control in the jungle, since 99% of the time it's "attack and kill everything at that camp" anyway.
It's not the level of control that Lycan has, but Riot has said multiple times that they won't make a champion that summons things you can directly control since the client struggles with that. The closest you can get is
; and Riot has expressed interest is reworking how he functions.