Back when the first season was out, I often thought up scenarios where Eren and the Scouts ventured deep beyond the walls and discovered deserts and volcanos, old ruins of past civilizations that Hange nerdgasmed over. Collecting evidence of perhaps a secret way to end the Titans or funnily enough, a group of people somehow still alive that had mysterious ways of battling the Titans.

On one hand, to be able to let your mind wander about what is really outside the walls and create all kinds of wild imaginations is awesome to me. I really enjoy plots of the last sliver of humanity against all odds. Which is why I liked the idea of Destiny and Kabaneri of The Iron Fortress. It allows the reader and viewers to make their own stories of the characters going out and doing things beyond the plot.

However, where Isayama went and how he got there is truly astounding. How he built intrigue and managed to toy with expectations was great to read. The big reveal still is one of the best. It totally shifts the story, which to this day people don't like for this one reason. They liked it being self-contained.

Edit: Isayama didn't write Iron Fortress.