Mother 3's story is overrated.

[Saltonara]

Everyone in the game would be wiser and forsee the danger coming, I feel so many of these problems in the game would have been solved if everyone knew the truth ahead of time.

If that had happened then there wouldn't have been a game. If anything the point of the story could be to make people realize that you shouldn't just ignore the past, because as you said, look at what happened to the people of Tazmilly. I don't see how showing the possible (not that anything like this would happen for real relatively soon) dangers of being completely ignorant makes for a bad story.