Why Does Mordekaiser Have Health Costs?

I really don't know the answer to this. This isn't intuitive at all especially with how meaningless the shield gain is when it decays so quickly for such a high health cost.

The biggest one is his Q though. Why does this have a health cost? It requires him to be melee on a champion with 0 mobility or CC - not even a slow. And yet it comes with a health cost. Just doesn't make sense to me. Prime example of major risk with minuscule reward.

This design made sense back when he was released, since he was meant to be extremely strong and gain defense from attacking multiple targets, basically making him the 1 man teamfighting pentakill machine. But nowadays he deals pretty negligable damage especially for how much mobility he has, given champions like LeBlanc and Ahri have just about the same survivability but with far more (reliable) burst.

What I think should happen? I think health costs should be removed and early ranks of E should have a higher cooldown to emphasize the gap between when his shield is up and down during laning phase (especially since it'll become "free poke"). This is to follow Riot's philosophy of making clear cut strengths and weaknesses. His strength should be his ability to gain shield when attacking, letting him win trades. But the weakness should be the lack of shield afterwards where he is vulnerable and his abilities are on cooldown. Basically making shield management more of a pressing matter. Late game he should function the same other than ofcourse not having health costs. But that's only for his E. As for W and Q I feel they should stay the same since they require you to be in melee range which opens you up to poke and ganks. Mordekaiser's viability as a lane pusher shouldn't be touched (early E cooldown increases shouldn't affect this part of him at all).

Also, let him put his W on turrets! Gives him a little more in terms of counterplay to ganks during laning phase with the recent "magnetism" buff. As it stands he is one of the most gankable champions in the game if not the most.

I also think a big reason why no health costs would be a problem is the way his ult pretty much gives him his entire health pool back. This just feels like excess power if health costs are no longer involved and should probably be removed. And with that mechanic removed, there's more room to buff his base health pool or his maximum shield or both.