Unless someone can give me hard evidence that we will literally be missing something we give a shit about unless we COMPLETELY restart, we'll be doing one of two things:
1. Making a new world with a portal between the two.
2. Making a portal to some point insanely far from our current stuff, and you can port out there... it's procedurally generated... there literally is no "fresh world" concept. Just keep walking.
It takes like 2 hours to get yourself completely decked out with diamond shit and a new house/workshop.
If you want to start over, dump your shit, get ported out to god knows where, set your spawn point there, and have at it.