The only reason tanks are doing fine in summoner's rift is because they're now assassins
Volibear can literally one shot juggernauts under tower. Mundo's Q has a 2 second cooldown and can 3 shot you. Nunu can go 0/2 and one shot juggernauts while stunning and slowing an entire team. Malphite builds assassin and assassinates you.
Riot, if your balance team is ACTUALLY trying to balance the game they are truly fucking shameful human beings that should be cleaning fucking toilets not using their minds.