I'm sorry, but I have to disagree. With most of what you said, actually. From my viewpoint, you just listed a bunch of reasons old Morde was boring. Honestly, I think new Morde is much more interesting, to play with and against. Let me explain:
there was no huge mechanical plays to be made, there was just me, the enemy laner, and the decision to fight them or not. i had to rely on great positioning and knowledge of my opponent's power spikes and how they worked with the items they bought...
First off, this is the one point that I completely agree with you on. Not every champion needs to be mechanically complicated and "flashy" in order to be interesting. I really do appreciate that some champions are more about strategy, positioning, and tactics, rather than mechanical execution.
if you fought him and you died, you outplayed yourself.
Here is the problem. You point it out yourself. Mordekaiser lacked the ability to outplay. If you won as Morde, its because the enemy wasn't good enough, not because you did well. And that's because there wasn't even much strategy/positioning/tactics involved with Morde, let alone mechanical complexity.
and he was not afraid to stand and fight, instead of running away after short trades like most other laners with the unholy amounts of mobility they tend to pack these days
I didn't want the ramp up damage. I liked his instant burst that punished players who played like pansies, but rewarded champions with the balls to stand and fight morde.
Now, these two points are kinda confusing. First you say that you liked how Morde could stand and fight, rather than burst and run. Then you say that you prefered how Morde could burst, but sucked at longer trades. But I think I get your point. Morde was (and is) not mobile, so his only choice was(is) to stand his ground and fight whenever his oppenent wants to trade. But before he could only do that well against mobile/bursty champions, and now he is more suited against all-ins. To me, that is neither here nor there. But I can understand that you don't want his strengths/weakness to be changed arbitrarily like that.
I didn't want morde's W to get a passive that encouraged laning with another player. I'm a solo lane main. I don't like you. I don't want to lane against 2 other players, I just want to fight man to man.
Here, I'm going to show a little of my bias. Being an adc main, I find it more interesting to play 2v2, since there is more going on in that lane. But I'm actually kinda torn here. Because I like that Morde is now an interesting new perspective on the bot lane meta, but I really don't think it should be at the cost of his solo-lane fans. His W is kinda a mess right now, and I hope that they can bring his solo and duo strength closer together with further tuning. If they can fix his top-lane performance, then I think his new W actually did more good than harm, because it opened up a lot more team-comp possibilities.
I don't want morde's W to give him sustain. he didn't need sustain to kick ass before, why should I require it now?
This... this is just pretty much false. Morde's passive IS sustain. It is (temporary) health that he gets over time. Besides, spell-vamp has always been pretty good on Morde, which is definitely sustain. I'd go as far as to say one of Morde's defining characteristics is that he wins his lane BECAUSE of sustain; the only caveat being that he has to hit a bunch of minions for that sustain.
I don't want morde's E to scale off of AD. AD morde sucked in the past, and AD scaling just makes his build path far less coherent.
You say "less coherent" but I hear "too straight-forward". I like diversity and options, and that is what the AD scaling has given to Morde. I'm sorry if you have to figure out a new build for him, but other people have done the work already. You can look up a decent build and use it in every game if you want. You can go full AP if you want (I think it's still viable). And, unlike before, now you can branch out and take a Triforce or Sterak's or Gunblade, if you want.
I don't want morde's ult to get a pet dragon. I don't like gimmicks that are only available situationally. I don't want strength that is not available to me all the time. it makes him far harder to balance.
Okay, I have to give you some credit on this one. The dragon pet is pretty messed up right now. IMO, it's a little too strong when you get it, it leads to snowballing, and it's pretty braindead (just press R on the turret and the dragon takes halfs of it's hp). However, it does mix up the game strategically by putting emphasis on dragon control and on what happens after Morde gets a dragon. It's something people are going to have to learn to play with/against. And about it being situational, you can always work to achieve that situation. Dragon is going to be a part of every game, and it's up to you and your team to get into a good position to take it, every game. As a counter-example, Yasuo's ult can be actually quite reliant on what specific champs his allies pick. So yeah, the dragon ghost could use some work too, but I think it is a good addition to the game.
I don't want morde's Q to require 3 strikes. there are plenty of other champions that do shittons of damage on the third strike, and they are far more mobile and can do more damage in the long run than morde can. Jax, volibear, xin zhao, vayne, among others.
I'm not really sure what your point is here, but it's important to remember that Morde can be similar to other champs as long as he is also different is some ways. He is more early-game- and team-oriented that Jax, does more damage than volibear, is less mobile than xin, and obviously isn't ranged like vayne. And none of them get way tankier when hitting people. Just because Morde has a three-hit ability, he's not a copy of any other champ with one. And once again, I gotta say, I think the three-hit, ramping damage makes morde more interesting, because there's more you can do with it and against it.
So yeah, everyone should know by now that League of Legends is a game of "skill/mastery/gameplay/counterplay", or at least that's what Riot wants it to be. In my opinion, old Morde was not up-to-par by those standards; now, he is at least well on his way to a better spot.
Now I also miss 
player I feel you. (Although her rework turned out alright, she was basically deleted from the game.)
until they decided that she needs to be a sustain-tank/bruiser/ap/ad/assassin/passive-oriented/fighter/jungler about forever patches ago, with even more identity problems than ever before. I just want her W passive back where she got movespeed from hitting enemy champions. RIP what was going to be my favorite build ever in LoL 
(or 
)
, who went from being an assassin to requiring tank items to be usable.
