If mordekaiser's rework was reverted, a simple way to balance him is....
Make his shield deplete up until a certain amount like it does now. Revert every god damn thing about him and you'll still be able to play him as a strong ap mage/bruiser and is still pretty much like a juggernaut, you get in range of him, you're in trouble.
If the changes were to be reverted, but you kept the shield depletion up to a certain percentage he would be:
- Less oppressive in lane in which people would have an easier time to trade with him
- Still be, if not weaker against high range opponents like he's supposed to be
- Still have his strong late game as an ap metal burst mage or bruiser like he always has been
You might still be able to bring him bot if you reverted the god damn changes while keeping that shield depletion change, but he will once again be fine for other lanes as he'll have better wave clear, and stronger trading skills.