>>58701544I agree, it doesnt need a type change.
Earth Eater alone makes up for Steel/Rock's typing being dogshit.
Having 1 4x weakness isnt that bad, a shit ton of viable Pokemon have that. Garchomp, Heatran, Scizor, Dragonite, Kingambit, Lando-T, Gliscor, etc... you get the idea. Its when you have 2 that it gets dicey, literally double the opportunity for coverage moves to KO you. And when the 2 types are literally 2 of the most common physical coverage moves, Aggron doesnt do its job anymore.
Swap 1 of those 4x weaknesses into an immunity, and not only is that issue alleviated by exactly half, but you've now got an awkward to deal with type combo. Steels that float are famously difficult to deal with, but typically they do it via being part Flying, and thus weak to Electric and Fire. Aggron obviously isn't. IMO its well balanced by the fact that it does still retain that 4x Fighting weakness, so its not some unkillable wall suddenly.
Whats cool about that too is, it fits its existing lore well enough. Aggron technically eats iron, but its not crazy to think it eats through other shit too to get to that iron.