Every other mechanic in the game, barring %hp true damage, has an answer to mitigate its impact.
% damage reduction ---> true damage
Mobility ----> grounding/silence
Immobile powerhouse--> slow
Healing -----> grievous wounds
Stealth -----> pink ward Riot: "fuck you these champions deserve to be uncounterable"
No, I'm not talking about camouflage. I'm talkimg about true stealth.
Because pink wards negating invisibility lead to them either being useless above mid-silver (when people finally realized that you could completely negate a part of someone's kit for just 75g) or absolutely mega-busted below that (If Riot buffed them so that they were viable despite the fact that they only ever had 3 real abilities).
There was no winner in that scenario. Someone on the opposing team could never go above 5 items because they needed to keep a pink ward at all times, and the person on the invisible champion got fucked because one of their abilities was never useful.
Stealth is countered by good positioning.
Understand that the ability to go invisible soaks up a lot of power budget from a champion's kit. In virtually all cases, they are going to be significantly squishier or do less damage than a non-invisible counterpart.
