the problem is towers and that's for a few reasons.
Tanks are so dang strong and have resistance that you can get dived by them and can't dive them. So I'll take the tower that belongs to top lane.
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Mid lane whoever gets first blood is just going to win the tower within 10 minutes
Bot lane is the same as mid lane but faster because there are two there attacking one tower.
Junglers generally are assassins with a lot of damage who just snowball with kills and help the laners take the towers faster. Infernal and mountain drake pretty much decide who wins the game. Especially if you get 2 or more infernals on the enemy.
But yeah towers are just weak af right now and riot won't do anything about it because "hurr durr we want faster games".
the way i see it is the faster games are pretty much synonymous with snowballing, which means you can pretty much tell which tower is going to fall and who is going to carry the game.