If Morde is nerfed out of the game, Riot's goal of Champion Diversity is nothing but Lip service.
For context, On PBE his w's DoT damage is halved as it no longer does double damage in the overlapping zone with his ally, it's healing is reduced to two targets from three with only a 25% ratio on minions from 33%, and it has a health cost that further nullifies his heal, netting 10 to 40 hp vs minions depending on level, from 50 to 130.
He can cast it on himself solo now, but only the ending damage/heal functions. The ending damage has been increased just under 50%, which lets it maintain healing parity in the jungle, but overall its a much worse ability overall. Sure, he can now heal himself for 10 hp every 12 seconds in top lane or even 45 if he hits his enemy laner, but that's not enough to compensate for his lower armor and his w being significantly worse outside of early lanning.
The MS now scales based of how directly you are running towards your ally, eg its halved if you are running at them at a 45 degree angle, which while strictly worse (still maxes at 75) is quite frankly an awesome change that I'd like to see on all conditional MS boosts, such as Vayne's and Janna's passives and Righteous Glory.
He also lost 4.88 armor early game, 4.25 of of which he gets back by level 18.
I'm quite worried that even if these nerfs to Morde don't effectively remove him from the game (although his jungle is looking promising if you can fit in your comp), other nerfs later on might, and if this happens Riot needs to think long and hard what their stated goal of champion diversity is.
Bot lane has always had the most stagnant meta, but as of late its been Janna, thresh, Jinx and Vayne have been ungodly common. In 4 years sans a very short window of double relic shield, I've nothing but a few very similar markswomen (in itemization and effect, if not play style) along with a support (who do vary quite a bit).
Since season 2, its ALWAYS been an ADC meta. Forget seeing assassins half the time mid lane, or tanks in two thirds of the jungle, these are all secondary to the dominance of ADC's (and their babysitters).
Morde has been the first champion to challenge this. I hope more will come, but until then HE needs to be viable; More so, he needs to be strong, as he's a risky, team reliant champ that won't see play if he's outclassed by ADC's.
Morde's win rate is not that impressive (51% overall in ranked, roughly, although his win rate is closer to 53% in NA), once you realize that sites like Champion.gg are dropping over 40% of his games due to Riot's API misclassifying him due to his weird build path, especially when gold starved, as multiple rioters and a champion.gg dev confirmed on my reddit post here.
Morde could certainly use some tweaks, with a slight power nerf, but noting his statistical strengths the question then becomes why isn't he allowed to be strong in the 2-6% of games he's in, while champion like Ahri, Jinx, and Vayne are allowed to be strong in the 20 to 40% of games they are in?
With his extreme reliance on his teammates, and his enemies making mistakes, what makes Morde more toxic than these champs?