So you guys play whatever is the best in the current meta. As such, you hardly ever ask for nerfs or complain about class balance. You simply switch to the next best.
I am not saying you are doing anything wrong, but I am just trying to point out exactly why you think warlock is NOT OP. Because for you it simply isn't. You play builds that are up there in power, and the builds that aren't, you just don't play.
But some of us don't play like that. We like certain archetypes, and we would like to keep playing them through different updates. We don't necessarily want to be the top1 FOTM build in terms of power, but we don't want to be totally outclasses. We believe that game balance should be important, and that it cannot be that some classes / builds are so much ahead of others.