Board Thread:Manga/@comment-27321453-20180708204808/@comment-26495049-20180725161240

Side01Winder01 wrote: Number 1 isn't necessarily mass genocide. Based on Eren's recent actions, he wants to crush the world's militaries, not the entire nations themselves. He seems to want Willy's plan to come to fruition. When the world unites and sends a giant army to attack Paradis, Eren will use the Wall Titans to smash the army, thus rendering the world militarily impotent for a time as well as frightening them into submission, thus making sure they won't attack again for a time (he's likely hoping for enough time for Paradis to modernize). At least this is the impression I got. Yup, that was exactly Zeke's plan. Which is exactly the 3rd outcome I've described above. If it takes 50 years for Paradis to modernize, it means most of our main cast will be dead (in particular the 9 titan shifters) or very old by the time that happens.

From an out-of-universe perspective, I don't think Isayama will follow through with the "50-year plan" for that reason alone.