Knockup and Tenacity: can we replace some knockups with knockdown+stuns?

Mostly to make tenacity useful again. I understand that this would make Yasuo ultimate more difficult to use, which I'm not sure how to address or if it should be addressed.

An important aspect of knockups is that they can stop dashes, unlike stuns. While it sucks that there are so many knockups around that bypasses tenacity, it's also true that there are a lot of dashes that should be stoppable. So I think it would make sense to take the benefit of both, and turn some knockups into knockdowns (like Poppy W), which interrupt dashes, and stun them afterwards.

I think most short duration knockups, such as Maokai, Vi, or Sejuani, should be changed. Those with very little CC otherwise or having a knockup that is central to their kit, like Yasuo, Malphite, or Aatrox, should keep their knockups.

What do you think?