I would pay a subscription for a version of the game that allows you to create persistent open worlds.

Concept too long for the title:

Basically, it would be like server hosting, with more people allowed, and the host could always shift. No cheats would be allowed, potentially, depending on the initial setup, to make things more interesting. Characters might be tied to a persistent setup.

I like building big, complex things in survival modes that take a long time. The problem is, people stop hosting their servers and whatnot.

I feel as though Valheim is a great starting concept for an even more complex type of MMO or persistent world type of game that could also be its own emergent RPG. I've seen aspects of this concept before too, but Valheim pulls it off better in terms of flavor and controls.

So, there are multiple possible directions, but I would absolutely pay a subscription if the servers were centralized and persistent. This also seems like a more sustainable business model. I want the devs to have the money to keep investing in more people and resources to make the game better.