my rebuttal for people who say "class name here" is op

(Insert class) is "OP" if a "Good player" is using him/her.

The main reason Assaults are OP is that there aren't many good gunners in pubs to counter the assault.

Assault < Gunner < Sniper < Assassin < (Support) < Tank < Assault

Support doesn't really fit in, but if it countered anything it would be the assassin.

I'd say it counters the Assault actually.