Mordekaiser: Iron Man passive
This is only a suggestion and any numbers given are only to emphasize the point of the suggestion.
Iron Man as is feels unsatisfying due in large part to the fact that it gives temperary HP. This is because that HP is good earlygame but not so much late since you need defenses to make that HP feel good. As is this heavily splits how Mordekaiser favors his item buys because getting alittle AD and alittle AP and alittle Armor and alittle MR and HP very, very restricting.
My suggestion, Iron Man should no longer give temporary HP. Instead it should grant % damage reduction based on 3 factors, total HP, current level and how full the Iron Man shield bar is. Earlygame this wont be very big and should let his base stats come up a bit. To compensate, this damage reduction should be very noticeable, something to the effect of a Level 18, 3000+HP, Full Iron Man bar granting around 50% damage reduction.
This gives a number of problems with current Morde a fix as it gives him his lategame fantasy, gives his E solid defensive power and evens out how satisfying his item build is since you dont need to build everything to try and feel powerful.
One last suggestion. Take the heal off W, that would make the suggestion above way to powerful to deal with.