Let's Talk About Tank/Bruiser Balance

Been a huge hater of Season 6 since this whole tank meta thing started but quite frankly it's getting old. I'm sure others would agree it's just not fun getting destroyed by a team of tanks that consistently solo you out for no reason. I bring to the table this truly cancerous example of what im talking about for those who aren't following...

This picture shows you a Rengar who has built Cinderhulk as his jungle item followed by tanky items and a Phantom dancer. So not only does this rengar have 3500+ HP, but he also withheld the ability to 1v1 me in a dual vs my rather damage focused build (built the warmog as a "Screw you for building like that"). So here's the thing. What is stopping people from building 3500 hp on everyone? Didn't there used to be different classes of champions in the game? like assassins? Now it seems people just build a damage item or 2 then go full tank and just clobber people from 100-0 instantly. If at all possible, could Riot possibly decrease all Base damage and make this game more item based? IE. Build damage to hurt, Build tanky to block, not Build 1 AD item and then full tank + base damage just instantly fuck someone over. Completely ridiculous that you can get away with both and be unstoppable.

Please tell me what you think in the comments and keep the downvotes a minimum if you disagree.

TLDR: Fuck the ability to be a tanky 1 shotter. Base damage too high on everything. Nerf plox rito [slayer-pantheon-thumbs]

Edit: Here is the damage numbers from the game https://gyazo.com/e4b9c80924c6b2dcff61b0efd51113ae