I definitely think with a limited world size, a compromise would be having events happen, maybe like in DayZ, helicopter crash site, ‘you hear a loud crash and see plumes of smoke in the distance’, cue showing it on map, NPCs will find it attractive to loot so you’re likely to encounter hostile NPCs there, and soldier zombies.
Cults spreading, building monoliths, trying to manually create tears in reality, maybe giving NPCs a goal of building houses or smaller shelters in safe places and storing items there.
new tears in reality, resulting in artifacts or other rare items, spawning otherworldly monsters, these rifts open and close with time to prevent the world from being flooded with too many mi-gos, perhaps a way of locating events like these, maybe a high electronics skill frequency detector that points the direction of tears in reality?
A static world size, with events, and mandatory having all overmap specials exist at least once should keep the game fun and fresh.
Events happening in a finite world hardly matter, your world going to shit doesn’t matter if there’s more world yonder.