I think what may be cooler would be turning the Voidlings a little bit of what they used to be.
Cooldown: 14 seconds
Passive: Casting Malzahar's other abilities lowers this cooldown by 7 seconds affected by CDR / 50% of the cooldown. [so two spells refunds the cooldown]
Active: Summon a Voidling for 21 seconds. Every 7 seconds it upgrades. First upgrade after 7 seconds is growth in size with 50% increased damage and defense. Second upgrade after 14 seconds is frenzy granting it 100% bonus attack speed. (They keep their magic damage and AP scaling that was added on.)
So essentially it is Malzahar gets one powerful Voidlings that needs to grow up after 7 seconds, with much higher defense and attack power, and to have the swarm of Voidlings is based on spamming your other abilities - so CDR and mana creates more Voidlings and his army from the Void!
Also most importantly is that the Voidlings become back like puppy dogs that follow Malzahar around and have a leash range, directing them with Malefic Visions and most priority with Nether Grasp.
These was the most fun Voidlings because each one feels powerful and its fun to just spam abilities, good players spam within reason, but still it is something that is fun for new players (Malzahar was my very first champion I ever played, all the way back in very early season 1) and feels like you EARNED your army of Voidlings rather than them being granted to you.
As far as feedback goes with Call of the Void, re-adding the delay is good as it makes the silence less reliable, but you need to re-buff the base damage a bit as well and maybe 0.25 second more silence time because the reliability of delay and no delay to land the Q is like night and day. So the Q will more than likely need more power back into it with the delay re-added.