There are already some huge maps out there, Just Cause 2 and 3 both have maps at around 1000km2, and those games are beloved by their players. But if the next Cyberpunk game was announced with Night City now being the size of an actual large metropolis, say like New York, would you say that’s too big? What determines what “too big” is?
There are space games with procedural large scale galaxies to the point that the entire playerbase can only ever hope to see ~15% of the systems, but that’s why I put the >50% qualifier in there. That’s TOO big. Anyone can generate an effectively infinite procedural world, I want a large world.
When I had originally conceived of this, it was in the context of a pokemon MMO. You would have your home town, and as a trainer, or researcher, or rocket member, etc, you’d travel at a real-time pace akin to the show.
Alternative IP that it could work with are dragonball (imagine the playerbase on a months long search to find/fight over the dragonballs so they could awaken the dragon and make a wish to the devs), or Avatar (each player would have a chance to spawn in as a random bender. One player at any given time is the Avatar. Events happen to strengthen some benders and weaken others. Players make war and peace at will).
There would obviously be challenges in running these types of experiences, but currently it feels like the cost of standing up an MMO is so much that no one ever does anything interesting. Instead they just copy WoW.