Tanks are Worthless; Tanks are OP

I've heard both said and they're both true, at least in dynamic queue.

Tanks as damage soaks are dead right now. The pure tank items (Frozen Heart, Randuins, Thornmail, aegis) have been progressively nerfed (and Spirit Visage / Banshees Veil are about to be nerfed). The S6 last whisper greatly reduces the tankiness of tanks and is quite cheap. And the S6 masteries have amped up damage tremendously. If you are a front-line damage-soak tank, you will not last very long on the front line. You will die while providing little peel for your backline. Tanks are worthless.

On the other hand, the more damage oriented juggernaut/bruiser/offtank items are or recently have been quite strong. These include sunfire, iceborn gauntlet, hexdrinker/maw, titanic hydra, deadman's plate, sterak's gage, ROA (for AP champs), and others. We see assassins and adc's abusing these items (akali, ekko, graves, yi, fiora, etc...). These items are cheap, provide decent damage, and add just enough durability to live long enough to kill your enemies first. And true tanks, like malphite, that build some damage items are stronger than if they build pure survivability (even with so many ADC's and other ad champs, I rarely see a randuins picked up). When true tanks succeed, they do so by putting out substantial damage in addition to their cc. So "tanks" are OP.

Both are true.

In terms of semantics, I would not call the bruisers/assassins/adc's building tanky items "tanks". They are "tanky", not tanks.

I'd like it tanks as tanks were relevant again. But I'm guessing that's not going to happen until Riot overhauls the tank class in its entirety.