I'm not going to waste my time by trying to quantify my experiences. Even compared to Live servers, PBE is very erratic in the games and the range of players that you get and the purpose is more to give our feedback on the champions and designs as we experience it. The only thing I will say is that I've mained Morde since S1 and I've seen him receive a lot of minor tweaks over time. Though for at least 1-2 seasons he had no changes. No ratio changes, no buffs or nerfs.
I have never seen a Mordekaiser played in LCS. Granted I don't get to catch every game so I'd enjoy seeing some (if anyone has any links). The entire champion is very outdated. He was designed in the day when a shield of any sort was considered very powerful, combined with his unique ultimate. Now we have champions like Yasuo who have these massive kits AND a shield that they have to do nothing but hang back for a few moments to regenerate.
Now compared to everything League has become in the recent years, Mordekaiser as a whole has become a rusted suit of armor. What was once mighty has become spotty at best. Some games he is a juggernaught, other games he's made of copper. He's a great nuker if he has ignite and ult up, but otherwise his only role is to harass and push creep (without enough damage to push towers). I've actually really started enjoying his current iteration of W, it's got a lot of playmaking potential without crippling a solo-laning mordekaiser like it does on PBE.
Which brings me to the PBE version of Mordekaiser. As it was, his kit was a bit confusing. Now it's all over the place. Even the suggested items seem random. That's not to say it's impossible to do well on Mordekaiser. But it's possible to do well on any character given the right conditions. Especially versus the grab bag of players you get in any given game. But in all of the games I've played so far as Morde, and the variety of builds I've tried, it just ends up being not fun. Like all the fun I had playing the character has been sucked out of it. I don't mind pushing the meta. As a matter of fact I don't mind Morde getting reworked and changed. But with his current kit and the direction he's being pushed, it just doesn't work.
So instead of pushing him to be a part of this big "bruiser" update that is in the pipeline, please hold off and try other things with his kit. Or do a COMPLETE rework. As a matter of fact, I think it's time for him to get a complete rework. Focus on his "feeding off of disease" and metal theme. Even if he loses the ult. A minor tweak, or trying to shove him into the bot lane, isn't going to be the way to do it. It's just the way to get even less people to play Mordekaiser.
Nobody really cares enough about Mordekaiser (as opposed to Fiora) to raise a reddit stink over this. The last Red post on a Morde thread on the PBE was about a Fizz ghost bug. All the data and rationale seem to just be ignored. It just sucks when it feels like my feedback isn't going to have any outcome when that's the whole supposed purpose of the PBE. All signs point to Morde changes being deployed next patch for better or worse.
And for a rework that's so unfun, it's just going to kill my interest in playing the champion when he comes to live. But at least you have all my money for all his skins over the last 6 years. Champions that have been released and reworked multiple times have gotten a full-on rework treatment. Why can't Morde? Hasn't he aged enough yet?
TL;DR: Push back Morde changes for a later patch. Please test more variations in his kit before you push him to live.