there are two rules about janna tornado, the first rule about janna tornado is we do not talk about janna tornado

the second rulea bout janna tornado is we do not talk about janna tornado!

A wild Zileas appears.

if you was to reduce knockups and knockbacks the only way i could see it working is giving some items a separate tenacity of weight since if your heavier you would be harder to knock up/back but then with that logic yordles should be knocked super high and fully stacked cho and gragas would be immovable objects so it would make more sense to give every champ a weight value for how far they can be knocked which would just get really messy or maybe just make anti gravity items and jetpack and everyone can fly XD

Well I think instead of making tenacity affect knock ups It may be more interesting to make a new defensive item for people who need to not be out of position (carries, supports, burst mages?) the first thing that came to my mind was

Hextech Lodestone

Knockup effects instead stun for half their duration (not affected by Tenacity)
Pull effects reduced by half (ie Blitz pull, Darius pull, only move you half the distance they would normally)

although I have no idea what it should build out off but I feel it shouldn't be super early game. perhaps the 10-15 minute mark if you rush it, say a 1700-2500 gold item

(edit: oh god you cant move/peel a singed off your team if he has something like this)