Good for servers, because it would stop people from traveling to the nether and end. and a realistic modpack, where you would not want there to be other dimensions.
A simple mod that sends you to world spawn if you attempt to enter another dimension.
This would change the way you would play the game because you cannot beat it and have no goal. This would possibly enhance creativity by encouraging exploring and preserving the overworld, as it is the only thing you would have.
