I have no clue what the nerfs to Morde on PBE are trying to achieve, his solo lane is even worse.

Yes, some nerfs, and more importantly power shifting, are needed to make Mordekaiser healthier for the game, and remotely viable in solo lanes.

However, on PBE Morde's W has been completely gutted; even though it can now be self cast for the heal (not the dot), the heal has been nerfed to only effect 2 targets, and heal 25% vs minions instead of 33%. It got roughly a 33% increase in damage, which negates the conversion efficiency, but not the reduced targets. But more importantly, it got a health cost, from 25 to 45 depending on level. This means its a net heal of 10 hp to 40 hp vs minions. Another 10 hp every 12 seconds puts him about on par with the vast majority of champions for HP regen, and doesn't come close to covering his increased HP costs on his q, let alone his e.

His W's DoT damage with an Ally has been halved at level one as it no longer overlaps for double damage, even though it did get a slightly higher per level scaling, and the MS is now reduced when you are running towards your ally at an angle. At least solo lane Morde's W is useful right now when team fights began to go down, on PBE it sucks at all stages of the game.

His armor is reduced early and mid game, lowering his ability to solo lane even further; I fail to see how he wouldn't be worse off with these changes.

Removing the W overlap damage is a lost chance to balance his solo vs duo laning; if it had been kept (but had its damage reduced to 80% of what it is or so) having Morde's DoT ALWAYS apply to himself, whether or not he has an ally to apply it to, but shared with his ally when the ally is with in its range, would preserve and clarify the skills team oriented game play, without leaving solo lane Morde in the dust.

These nerfs hurt duo morde, but mostly just shift him from maxing w to maxing q; solo lane is hit the hardest, as he was already maxing q (or e, but its health costs are ridiculous for how little damage it does). The only one who benefits from this is Jungle Morde, as his w does give great sustain in the jungle.

These nerfs do little but remove Morde from the game.