Mordekaiser himself is not what makes Mordekaiser broken

I was wondering what made Mordekaiser so op after getting smashed by him in lane one day so I decides that I would find out for myself. Upon looking at his base damage and scaling, I was surprised to see that he has some of the worst scaling out of any bruiser. His Q at max rank has an abysmal 155 base damage with 60% scaling. While you could make the argument that his Q has up to 40% increased damage on single targets, I’d also make the argument that if he was a physical damage bruiser, these numbers still would not fly. My point being that isn’t it strange how the bruiser with some of if not the worst damage in his class who relies on ap items managed a 53%+ winrate until his nerfs? The champion who still to this day terrorizes melee top laners with his patented Seeker’s Armguard/Ninja Tabi rush. Is this a coincidence? I think not.