I have an idea for a mod. It would be a dimension type mod where you can travel to your other saves. Say you have a World 1, which is your main world. Then you generate a World 2, making it a flatlands or something special. But the problem is, you want to use what you have in World 1 in World 2 without having to spawn anything in. That's where this dimension mod would come in handy. With the mod, you could make a portal, configure it to go to World 2, and then go in the "World 2 Dimension" with all the stuff you had from World 1. Sort of like Terraria's Player+World system. So, what do you think?
World Save Dimension Mod