Shorter games are not fun
It allows cheese things like Ziggs bot or no tanks to run rampant untill late game, but then late game never rolls around. Turrets don't protect, there's always 4 man turret dives, and the game is decided in the first 10 minutes. With faster paced matches the person who gets ahead with a few kills can be so dominant, that coming back before the game ends is near impossible. There's so much information changing, such as keystones, new items, and new champions, ect its overwhelming. Nothing is more frustrating than not knowing why you lost. As of right now, winning a game feels okay, but losing a game feels horrendous. Its not worth hitting the play button knowing winning a game is not worth the headaches.