That was a description of why she was so difficult to play against and was easily one of, if not the, most frustrating hero to play against for many players.
None of that made her “overpowered.” Just because you or any number of people don’t like a hero or struggle against them does not make them OP by default.
Hero balance is not, and should not be, determined by popular opinion or vote. It is, and should be, determined by statistical performance, which is measured exclusively via winrate.
“Little counter play,” is correct. “Way too strong,” is not. Her winrate was remarkably average.
And yet, Diablo is the second worst tank in the game right now, second only to Muradin.
If you want to talk about strong Tanks, ETC has better sustain, damage, and CC, Johanna and Arthas have more utility and disruption, and all three of them have better waveclear. Literally all Diablo has going for him over other Tanks is his swole healthpool, and it shows in his 46% winrate.
Banrate is a measure of opinion. Opinions can be wrong. If people are banning a hero, that in no way means that the hero is too strong. It means people don’t want to play against that hero because they think they are either too strong or too frustrating to play against.
No, it means people think something is wrong, regardless of whether there actually is anything wrong.