Riot's official reasoning for gutting galio was that his W "Gave him too much ability to force fights". Now, I'm no professional league savant, but, as someone who likes to play and watch league, it was kind of my impression that a tank's purpose was to start a fight favorably.
Perhaps maybe, just maybe, Galio's ability to start a fight as a tank would be far less problematic if there wasn't so much burst horse shit from every champion and item in the game where 1.5 seconds of CC is a 100% guaranteed death sentence no matter what.
But, that won't happen because that starts the entire rabit hole of making positioning and preparing for the team fight relevant, and Riot might actually have to analyze the game, and the concept of roles and minor victories. Its much easier to just make the game a go face brawl and shit on champs like Galio.
RIP Magic Stone Bird