People would probably become more altruistic. Since there's no point in being selfish when the end is near, they might start sharing resources freely and helping others without expecting anything in return.
People's behavior would change drastically. In the beginning, there might be chaos as everyone tries to figure out what to do. Some would hoard resources, but as time goes on, many would realize that there's no real point in that. There would be a sense of community among some, where they come together to support each other. Others would isolate themselves, not wanting to face the reality. And families would either grow closer or fall apart depending on how they handle the stress of the impending end.
If we consider a world without black people as described in the story, the educational system would lose out on the knowledge and wisdom that black scholars and educators bring. Black history, which is an integral part of world history, would be absent, leading to a very incomplete and inaccurate view of the past. This would also affect how future generations view the world, as they would not have the full spectrum of human experiences and achievements to draw from.
The world might become more aware of the power of imagination. Since 'The Never Ending Story' is full of it, people could start to value creativity more.
The ecosystem would likely thrive without human interference. With no more deforestation, forests would expand. Animal populations that were previously threatened by humans could grow. For example, large predators might return to areas where they once were hunted out.
It could be in a film adaptation. Sometimes filmmakers think a different ending would work better for the cinematic experience.
You can change the ending by introducing a new twist or event that wasn't expected. Maybe a character makes a sudden decision that alters everything.
If the Phantom is accepted by the public in an alternate ending, it would change the message to be about acceptance and the ability of society to look past physical differences. It would suggest that talent and a good heart can overcome prejudice, and that everyone has the potential to be part of a community if given the chance.
Well, think about the themes and messages you want to convey. Maybe tie up loose ends or give a twist that surprises but still makes sense.
In the beginning of the story, the shepherd boy was mischievous. He thought it would be funny to deceive the villagers into thinking there was a wolf when there wasn't. So he would casually shout 'wolf' and watch the villagers rush to his aid. As he repeated this behavior, he got used to the false sense of power and entertainment it brought him. But when the actual wolf showed up, his behavior completely changed. He was now in real danger and his cries for help were genuine, but unfortunately, because of his previous lies, no one believed him anymore.
Shen Li and Xingzhi ended up living in seclusion in the mortal world. In the novel Journey with the Phoenix, Xingzhi planned to destroy the Ruin Sky Abyss and bring the demons in the Human Realm Upon Heavens to their deaths in order to help the demons invade the Three Realms. Feng Lai rushed into the Ruin Sky Abyss and rescued Shen Li. In the end, the Ruin Sky Abyss was destroyed and Xing Zhi's consciousness disappeared. Shen Li placed Xingzhi's divine body in the Snow Sacrifice Hall. After Xingzhi woke up, the two of them lived in seclusion in the mortal world.
In the case of a new time - controlling hero emerging, it would introduce a whole new element to the story. The story would no longer be just about the existing heroes and Timetagger. It would expand the Miraculous universe by showing that there are other powerful forces out there. The new hero could bring new powers, new rules, and new storylines that could potentially lead to spin - offs or new arcs in the Miraculous franchise.