Morde Passive rework idea

A replacement for Mordes current Iron man passive:

Morde has routinely been described as Deceptively Tanky this is an attempt to keep that true while reworking his iron man Passive to the Ridiculous Overloaded standards of today's character design

What if Morde had a % Damage reduction That fluctuates based on Mordekaisers effective Range

( Warning ALL number values are simple amateurish attempts to help convey the ability)

So Morde is atleast LVL 6 sitting in base

With all abilities available his effective Range is 1000 units = 5% Damage Reduction

He cast W on an ally to help defend Mid inhibitor tower. his Effective range becomes 675 = 8% Damage Reduction. He Moves up pokes the wave with E Effective Range is 650= 10% Damage Reduction He cast his Ultimate on a enemy champion Reducing his effective Range to melee = 25% Damage Reduction His E comes back off cool down his damage reduction Drops to 8%.

Note: with dragon ghost Mordes Damage reduction becomes zero. Just a ROUGH idea that came to me.

What do you all think