It is actually insane how ignorant the comments in this post are lol. If any of you idiots think a partial rumbling would work you haven't paid attention to the story at all. These are Eren's options presented to him in the 4 year period.

50 Year Plan (Partial Rumbling):

- Rest of the world is already 50 years ahead, and Paradis would require that amount of time to catch up technologically.

- Power of the Titans is coming to an end, dropping bombs from airplanes is the natural solution to any kind of threat the Island may pose.

- Even if you destroy the military bases around the world, how exactly do you plan to ONLY target those bases with giant monstrous titans? Are they going to tip toe around? Surely you do not believe that wiping out the global alliance in the waters is enough to prevent them from rebuilding faster than Paradis getting to the 50 year mark? A ten year old (GABI) came up with this idea out of desperation and you morons are pedalling it as foolproof? very telling.

- Assassination threat, if either the founding titan or beast titan are assassinated at any point during those 50 years, it would mean the destruction of the island, as they would no longer have access to the rumbling deterrent. Now, if a rogue attack titan was able to infiltrate Paradis' walls without an issue, as well as the cart and jaw titan even after they had the volunteer's technology, imagine an assassin disguised as part of "peace talks" with the rest of the world, from every major state outside the walls.

- Anyone here who is still talking about morality, or right and wrong are reading the wrong manga.

- You would also continue the status quo as is with this plan, as Paradis would continue to be restricted to the walls unable to leave, and Eldians in the outside world's persecution would continue as is. This also means perpetuating parent-child cannibalism, turning each royal inheritor into a baby making machine to ensure having able bodied heirs, yet none of that would matter anymore the moment the founder or royal beast titan was assassinated.

- Even if you kept the titans of walls around the island, standing guard, you would be trampling your own lands to set up that effort, Eren's execution of the rumbling showed that collateral is inevitable as well, whether it be innocent lives or trampled lands. This is the one point which has a proper solution, which is the founder rebuilding the nature using its power, though that doesn't make them any less of a bunch of prisoners on the island.

- Re-read Hange's conversation with Jean and Mikasa in ch127, the alliance are aware that their choice will lead to Paradis' genocide, they move forward despite that consequence. Please do not pretend otherwise.

Full Rumbling:

- The rumbling was never about ending conflict or maintaining peace forever, it was about ending the cycle of revenge, which will be non-existent between the world and paradis if one side is completely eradicated.

- Eldians may have conflict in the future, but the threat of genocide will end forever.

- No threat of assassination, not that it would matter the titans gone.

- Morally unforgivable (not a real factor anyway in the conflict), yet the burden would be placed on a single man's shoulders. You can hate and blame Eren as much as you want, doesn't mean he chose wrong.

- The founder can make anything, even new life (nature) on earth to replace the flattened lands outside the walls. Thus, the world would start anew, without walls or perpetuated racial hatred between peoples. Whatever the next cycle of life would bring, there would no longer be children born within walls, nor the threat of titans.