Watched RedMercy patch rundown thing

At 10:05 he talks about how he doesn't even know what makes Sejuani OP cause it's permabanned... I mean what, a few days of good success leads to perma ban idk. On paper she does seem kinda OP but she has low DPS and no survivability outside of her engage. I've rarely gotten the chance to play against it and the few times I have I won like. I think the point I'm trying to make here is that community speculation is not right in this scenario?

I think she needs nerfs but it's all theoretical and I don't feel right seeing the champion nerfed based off theory.