Tank Rework wasn't a failure (Extremely, absolutely, most-certainly, positively popular opinion)
I'm a simple man.
I played a game as Rammus and lost.
But the teamfights lasted a while, the carries did damage if peeled for, and the tanks tanked.
Honestly, when taking a few steps back, I believe this was the 2nd best class update (to the Juggernaut update)