Old Malzahar had burst, because all he could do was burst. His Kit was designed around that only outlet, which left binary gameplay in fights. You ult a target, after combo'ing with Q-W-E of course, and hoped that that was enough to kill your target before ya got Cc'd. In laning, opponents are forced to fight passively, being constantly pushed under tower due to his superb wave clear, unless they could push as aggressively back (Unless you're Morgana, in which the wave dies and both of you walk back to turret)
New Malzahar, is not focused around Burst anymore. Lower CD on his Q means he can disrupt a fight more, extend the length of his E, while constantly summoning Voidlings to help with a fight, by forcing people to deal with them, while they also disrupt potential skillshots flying around. In removing his Blunt force strength, they've given him more tools than "Combo target and hope they die", like Team fight control and disruption.
Yes, he does not play like Old Malzahar anymore, it's sad. But that was the point of the mage rework. It was to give people more options, slightly better build paths, and, the most important one, make it so not EVERY mage had to be a burst mage to function.
We now have champs who are meant to burst, like Brand, Syndra, and Twisted Fate. We have champs meant to disrupt teamfights, like new Malzahar, Annie, and Zyra. We have champs who utilize artillery, like Xerath, Velkoz, Ziggs and Lux. We have front liner mages, like Vlad and Swain. Even DPS mages, like Azir, Aurelion and Cass. Before the reworks, pretty much all of them were BURST, BURST, BURST, because that's all their kits were made to do.
Variation is good, and if Malzahar isn't fitting your burst sized hole in your heart, feel free to pick up other burst champs, but not every mage needs burst to function anymore.
TL;DR: Malzahar isn't a burst champ anymore, and we should stop comparing his damage to a Burst champ. He's a better DPS and Teamfight disrupter, and should be played that way.