Please return some variation of the old Q, where the blow echoed out, it was such a cool attack.
Secondly, do away with the mist clouds on his E. He is the master of metal, not the master of mist, and it was way cooler to see thick metal pillars erupt out of the ground and damage an enemy.
Requests for Morde's rework are probably going to be moot at this point, considering how far along he probably is.
That said, Mordekaiser being a ferromancer makes 0% whatsoever in the new lore. It was a cute gimmick when he was nothing but a walking bundle of metal music references, but now he's one of the most feared lich warlords in Runeterra. The metal gimmick is probably going to be heavily reduced, and I don't see it having much relevance to who he is as a character anymore.
