The patch that killed Garen
So I tried to play Garen a couple of normal games for fun but inmediately understood why I would never pick him in a ranked game. He is super slow and his Q ms boost doesn't feel impactful at all. Then I remembered.
V5.17 Stats Movement speed reduced to 340 from 345.
Decisive Strike: Bonus movement speed reduced to 30% from 35%.
Literally every class has items that also give 6-8% movement speed. Also there are again more high mobility champs added to the game since then. You can make Garens ult do 100%HP true damage it wouldn't matter because he can never get in range any way.