My take on Bruiser-Morde
Since Riot doesn't seem to know that tweaking numbers won't really help but that a full-scale rework or a gameplay update's needed I've tried to create my own take on Mordekaiser. This rework will make him tankier and shift him from burst to sustained damage like his thematics already hint at.
Passive: Iron man Mordekaiser converts 35% of the damage dealt into a temporary shield that decays 6% per second while out of combat. The shield value's calculated from 10%-15% of Mordekaiser's maximum health as well as a flat amount scaling per level. (Let's say 20*level) This change will help promote a tanker build while still making building damage a viable choice. My point here is to find the right mix between durability and offense.
Q: Mace of spades-> Hammerfall Mordekaiser launches his mace to a target location (600-650 range-ish?) and deals damage on impact. The damage gets lower the farther away the mace travels but Morde benefits from increased movement speed while moving towards the mace. If Mordekaiser picks his mace up a shockwave will follow, dealing another wave of damage and briefly snaring/slowing everything in vicinity. Damage: 20/65/105/125/155 +0.2 Ap (decays the further it travels) Explosion damage: 40/60/80/100/120+0.4 Ap This will help Mordekaiser in terms of mobility and escaping sticky situations while still leaving room for (situational) damage. If used in close range this ability will be great for dueling and brawls, which fits this bruisy-playstyle.
W:Creeping Death A bruiser needs sustained damage, doesn't he? So here it is, Creeping death will be Morde's primary sustained damage. This ability will be a toggle which drains a flat amount of health every second while providing some MR/armor and shield by dealing damage. This skill will be a damaging aura of shards originating from Mordekaiser and continuously deal damage around him, making him a force to be reckoned with in close quarters as well as giving him great wave clear. The health costs will be adjusted so that the power of this ability will be justified by it's cost. As well as dealing flat magic damage I'd add a max hp shred, which is applied in form of a stacking debuff (Rusted shards maybe?) that can be triggered once 4 stacks are applied on a unit by simply damaging said enemy.
Damage: 35/55/75/95/115+0.25 Ap Debuff damage at 4 stacks: 5/7/9/11/13%max health in magic damage
E: Siphon of destruction Mordekaiser's poke pattern is extremely anti-fun to play against so I'm going to remove this aspect but still make him kinda a lane bully by shifting the damage on to a secondary proc. Mordekaiser's one of the few hp-using champions that doesn't have any inbuilt sustain so I'm going to give him a minor heal on this ability's proc.(still aoe. The second damage is applied the moment he deals damage-> wave clear pattern= E wave, march in, use w to proc the damage) Damage: 35/65/80/100/125 +0.25AP secondary proc: 35/65/100/125+0.25AP Heal on second hit: 5% of max hp(promotes tankier approach). only heals for 1/5 on minions
Finally we come to his ult, which currently holds too much power cramped into one ability: R:Children of the grave This ability's simply too bursty for an ap bruiser so I'd tone down the damage scalings while still providing a decent amount of damage with it's %hp qualities coupled with a juicy heal and shield gain. The ghost's stats should be tweaked though and maybe allow it to mimic's Morde's creeping death whenever it's active although with lower damage
Damage: 34% max health damage + 2%per 100 ap
These changes would promote a tankier build as constantly using his aura of pain will cost him a lot of health and he'd have to be in the midst of battle which would mean he'd have to build way more tanky. By making some of his abilities scale with his maximum hp he'd also have to think about buying some health as it will drastically boost his survivability. Lastly shifting his damage away from his ult would make his play pattern more exciting than ult carry-> win game.
Any other suggestions how to improve Mordekaiser so he'd fit the Ap-bruiser fantasy? let me know

etc.