How to alleviate the Knock-up/Tenacity issue somewhat.

We know from Braum that knock-up durations can be adjusted to a certain extant, and from Blitzcrank that stuns can be tagged on to displacements to make sure they work as intended.

--> Reduce the knock-up durations where possible (meaning: where it wouldn't interfere with animations, effect, or doesn't feel too weird) and add a stun duration equal to the reduced amount. Tenacity then reduces the stun duration, giving it some value against knock-ups.

In most cases this would probably only be a 0.1, 0.25, or 0.5 second switch to stun time instead of knock-up, but every little bit counts during a CC-chain, right?

An example by Cho'Gath Q: 1 second knock-up --> 0.75 second knock-up + 0.25 second stun after you land. Now you can reduce 25% of the total CC duration with Tenacity or use a cleanse effect as soon as you land.