@Riot Aren't you guys being unfair to Kayle?
To be fair to Riot -
Since Beta, Kayle has been going through a cycle where she's 100% pick-ban, Riot nerfs her, her player base gets salty and moves on, a new crop of players picks Kayle up and makes her 100% pick-ban, Riot nerfs her, her player base gets salty and moves on, a new crop of players picks Kayle up and makes her 100% pick-ban, Riot nerfs her, her player base gets salty and moves on, a new crop of players picks Kayle up and makes her 100% pick-ban....
I'm sure they're slightly relieved whenever Kayle isn't in the spotlight, because she usually steals said spotlight.
Kayle also has...a very limited set of weaknesses.
She's one of the few champions that has moved between lanning positions with ease, being a solid mid-lane, top-lane, jungle, and support pick. Unusual compared to most champions - Kayle also maintains almost exactly the same build regardless of her lane position, being a solid duelist, jungler, AP carry, support, and even marksman with the same AP/AS stuff.
Unusual to most champions - Kayle has also generally been nothing but power-spikes. Early game Righteous Fury makes her an absolute monster. Mid game her AP-Burst potential make her a threat, and late-game her AP/AS scaling is pretty close to hyper-carry status.
It's not difficult to imagine Kayle running away with the pick/ban phase if she's buffed by even the smallest amount. She's just so versatile and so strong in so many different ways.