You're once again simplifying, and isolating everything from each other. You know what Malz's kill pattern was? Q-W-E-R, and if you put that all on a person, they're going to get hit unless they have god-like reflexes, but even if they flash, R follows no matter the distance.
And you talk about individual abilities functions and how to avoid them. That is true, but you are isolating them from how they are actually used in game. Malz never had to fear the jungler, because he could rather safely E a minion, clear wave, and then return to his turret waiting for the next wave, hence why he is rather low when it comes to being interactive. Malz was The Safest wave clearing mage once he backed. A Malz who used Q to poke is a moron, he doesn't need to poke, he just needs to get to Level 6.
You can't get close to your own minion wave while E is hoping around (it doesn't prioritize minions over champs), and if you're anyone who doesn't have the range of Lux, Xerath, Ziggs, than you're going to get completely fucked when trying to engage upon him unless the Malzahar is stupid. "But what if i catch him with the CC for my one shot combo??", well congrats, you're beating Malzahar the same way he'd beat you.
And I don't know where you're getting Squishy from. Early game, maybe, but late game old Malz could get some pretty nice health from ROA, Rylais and Liandries, with a Zhonya's for Armor. That may not be tank status, but that makes him a hell a lot harder to blow through.
In the end, Old Malz is a brick wall. You either smash the thing to bits with a Wrecking ball from afar, or you get nowhere against him, for he is a wall. Teamfights aren't as simple as you think, as Malz isn't going to stupidly ult the first person he sees, rather using it as a safety measure if someone get's close to him/carry. A Malz who holds onto his ult is one of the scariest things I ever had with old Malz, as I never knew when i was truly safe to try and kill him.
That a real enough argument for you?