Just You Wait, People. Yuumi is Likely Going to be Gutted
And it will have absolutely nothing to do with her performance, her pick rate, her play rate, or her ban rate.
I've seen cases like these in the past. And it always boils down to a new mechanic Riot introduces into the game that they then either nerf into oblivion, rework into something entirely different, or remove altogether.
In Yuumi's case, it is her W.
Never before in the entire history of league has a champion EVER been allowed the luxury of spending most of the game untargetable.
Sure, there are champions with abilities that provide them a temporary measure of untargetability, but nowhere near as severe a degree as is with the case of Yuumi. And hers has no mana cost, is given to her at level 1, and has almost no cool down while also having charges that allow her to spam it.
I am not saying Yuumi is overpowered (she may very well be). What I am getting at here is that this new mechanic is likely going to prove such a balancing nightmare for the balance team that we will likely see a patch in which Yuumi is destroyed.
I can only speculate as to how Riot will handle this new idea of theirs, but, given their track record, I imagine it will be bad.