Not contributing enough for the Viability thread, but it's not surprising that Banded HJK Mienshao 2HKO Gardevoir after rocks. You're using a STAB Banded 130-base power attack coming from 125 base attack, plus Stealth rock damage, which would 2HKO 252 HP/252+ Def Hippodown. Not saying Gardevoir is not fail, but still, that's not a very good example.