AOT is one of many butchered endings or endings where the mangaka was forced to keep writing by the editors.
For example in Death Note the real ending is where L dies. Light won. There was no need for the aborted wankjob editors to ask the mangaka to continue.
Full Metal Alchemist fucked it up too by reviving thousands of characters. Either they are dead or don't kill them in the first place.
AOT should have left Eren alive one way or another. What you said isn't the gist I got from the manga. Eren turned into a mass killer for no reason really and then the Eldians stopped him and allied with Marleyans for no reason when they were still recovering from surviving and were uncertain about their future as they had to get rid of the Marleyans who basically wanted to get rid of them.
Eren kept getting flipped because of the editors for sure.
The Mikasa Eran was a couple from the start, I don't see the issue with it. It was in the writing they were going to be together.
The fact they suddenly overcame all that power is also nonsensical and the fact Eren did nothing to stop them ...
I am 100% sure One Piece will slowly be butchered into a similar shit ending unless Oda does some drastic changes. He keeps diminishing Luffy's life span, because an all powerful good guy isn't allowed to exist in the manga story, only the all powerful bad guy.
