Supports have no counterplay.
In an effort to buff the most unfun role in the game, Riot has completely funneled almost all of the game's power into support.
Here's how to win games. Have your jungler gank bot once and get tower FB. Now your support makes your ADC an untouchable god king while being unkillable on their own.
There is nothing you can do against a Janna/Lulu/Soraka who just sit back and smash their buttons on their allies off CD. There is nothing you can do against an Alistar headbutt + pulverize combo. There is nothing you can do against a Tahm Kench devour.
Almost all of the game's problems right now stem from support. Jungle is problematic in its own ways, but bot lane is definitely a bigger problem right now. Most ADCs aren't even that strong on their own. Them buying Tabis is certainly an issue, but they still are squishy on their own.
and
are mechanically intensive and have high skill ceilings.