What is Mordekaiser?

I got in an ARAM game and I remember when I used to play him and I would just walk up to an ADC late game, press R, and deal 50% of their health and get them as my minion. Now days this guy is trash. Seriously, what is he? Tank? No he is just as squishy as any other mid laner. Assassin? His burst without 700 AP is like 25% of your health. Oh I know he is about sustained damage! Wait, every other character in the game deal 200x his damage. He is out ranged by almost everyone. Well maybe you can play him against melee champs? WRONG! He has 0 cc, not even a slow, what am I supposed to do walk up to and press E once every 6 seconds to deal minimal damage then get Q'd in the face and spun on? This guy is supposed to be the King of Suffering, but the only one suffering is him. I thought he was supposed to be this giant, scary, bad ass who you were afraid to lane against because he would sustain forever, but he uses health and he has no spell vamp early, and when he does finally get it anyone can burst him in 4 seconds. Honestly it would be safer to pick Taric top.