MAPPA has undoubtedly done a very good job since taking on the project. The ending of SNK was not at all easy to animate and they have done it brilliantly and quite faithful to the manga.
I will miss this story, I've been watching it since the first season premiered and no doubt it has marked many fans of this work. It has deeper themes than just the battle against the titans and that gave more value to the work, like everything you mention.
Buhito you are absolutely right, I started watching it just when it came out and it left me marked, every little aspect of that first season and the following ones became simply splendid. When the real main story of the war was revealed, I was in shock, but with more questions than answers. And with this ending I was left with a feeling of emptiness that still makes me shudder.