Poppy was a complete Re-do from the ground up, and Warwick just needed his theme solidified, thematically. Neither of them can be compared to Malzahar's gameplay update, because both of them had separate intents. If you're saying that Malz needs a Warwick level update, most certainly, but not the other way around.
Moving on to the rest, I don't care what people complained about. Even as someone who played Malzahar, he had some design problems. Little to no room for outplay, his first back for some AP let him easily push waves with E, and pretty much stopped an entire class of Champion with a click and point nuke. The most fun for myself, and sometimes my opponent, was when I accidentally summoned a Voidling that saved my life, a "Get down Mr President" though yes, nuking people with click and point was fun for me
Now, let's move on to "original design intent". Just because something was there first, doesn't mean it's the immediate right choice, especially when it has problems. Riot has made plenty mistakes in "Original design" like Vlad before his Mage update, which ended up creating a champion that was either over oppressive or just dreadful.
You also specify two different notions of "original design" when you talk about the champions reworks, while still using two separate comparisons one shouldn't make. Poppy's original design was kept from a Thematic standpoint, which fit into her gameplay. You then use that as a comparison as it should be with Malzahar, who stayed the same thematically, and only got changed in a gameplay sense. Two very different things being compared here, with unfair standards applied to one.
I'm gonna say this, and I know this is gonna be hard to hear, but that's absolute bullshit. Riot doesn't have a respect for previous design choices, because they have grown in the quality of their content, and see the older things they made a long time ago as a stepping stone, but one that has not aged well at all. They are perfectly fine ditching what they once made, in favor for a newer better version of the same thing, something they can say "I'm proud of this" instead of "Oh, well that was a long time ago".
Traditional skins for Poppy, Sion, and Warwick is one of the dumbest requests I've heard from people, because there is absolutely nothing worth keeping from those older versions. Old Sion was a meme, Old Poppy was a nightmare AND a meme, and Old Warwick IS THE EXACT SAME AS NEW WARWICK. They respect the past, but they don't oogle at it and put it up on a stand. They take it off the shelf, put it in Storage, and put out the newer version of it that they put more work into than the old one. (Ex. Lollipoppy original face on the Lollipop).
Aside from the Rant of that... you talk about a "yes space", which irks me for two reasons. One being, you act like just because people agree with Riot, they are somehow linked to an inherent bias, so their opinions should be worth less. Second being, that the people who are in the "No group" are inherently right, and can no way be wrong. Yes, Riot ignores what people wants, but sometimes what people want is not what Riot has in planned.
Riot did not want Malzahar to be so click and point nukey, yet people argue that's what they want. I've seen this a lot, like people complaining about Leblanc's delay times, when Riot's specific mentions are about giving people more time to react. This is Riot ignoring people who want to keep the unhealthy aspects of a champion, because that is what they are accustomed too, and have assigned to be the original design for the champion.
Riot ignoring people is not wrong. People play what they want, and like what they play for a reason, and they don't want to see that changed. But those are people we shouldn't listen to, the people who want insta-gib Leblanc, insta-gib Rengar and for no reason other than "This is how the champion has always been!". It's not an objective look on their own champions and the problems that plague them.
So yes, Malzahar has gotten more nerfs in one year than he has three years prior, but that doesn't mean that Old Malzahar was spotless. He had problems, and the rework has been trying to tackle those problems, but it's been a trial. There is no reason to stop doing something because it's challenging, especially when it's on a good path from intentions.
/midnight rant over