You know what's funny? I'm duoing a guy who used to be D IV down in Gold/Silver.
Last night we purely got carried by a Mundo, because we were vs a Sivir/Sona, who at least the Sivir was heavy smurfing (probably current diamond)
But even though Sivir/Sona got online.....
Our Mundo/Cho Gath were literally almost able to 2v5. Mundo was taking 30% of Sona's HP per Q, and kept on her with his W, and she couldn't do anything nor could Sivir. Nor could their Master Yi!
To paint the picture:
https://na.op.gg/summoner/userName=Aredethe
The 2/7/13 Morgana game (about 5 down)
I only had 11,388 damage received the entire game, but died 7 times. In other words, Sivir and Sona didn't waste ANY damage. If they wanted to kill me, they killed me. I never got hit by any other poke.
Mundo did over 5k more than me and died once, and soaked over twice the damage I took.
You might call this a Cassiopeia overall carry, but Mundo is the real reason we won. It's hard to show without wasting a lot of time trying to screen capture the game, but he controlled the entire flow of the game, which enabled Cass to do more of her job.
#Bottom line: The RIGHT tanks are very relevant right NOW. The challenge is: SUPPORT tanks generally build 2 HP items first and put off building Armor/Resist, so they don't feel like tanks. But Jungle Voli, Mundo, Cho Gath, Garen; those tanks are all doing fine. Ornn top can be downright oppressive if he's got a lead. Poppy is outright a game centerpiece (just not played that often because she's Poppy)