You wanna know the place to start in terms of Malzahar balance???!
It's really so fucking simple. TAKE AWAY HIS STUPID FUCKING RANGED SUPPRESSION ULTIMATE THAT IS POINT AND CLICK. If you want to keep his ultimate as a suppression tether, then at least make it a skill shot like Leblanc chain. He is so obnoxious in lane for his R and literally only his R. It's not that long of a CD even at rank 1 with 0%, it scales over 100% with AP and has a decent base damage to it, and as i said before it's a ranged instantaneous suppression that is point-click.