Hell I know battle royale games are memes now, but a game like Fallout is the perfect setting for a Day Z type of MMO game. It's basically like that book "The Road"--it would make sense that post-apocalypse people would turn on each other (PvP and players, some NPCs), and others would try to build communities (NPCs and some players). PvP is built into this setting so the whole "you can see people on your map and also just hear them". Hearing them is fine, but maybe like limit it a bit. PvP could get annoying for people doing quests and shit who arent into that though. Maybe put more shit in the terrain so even though people in the PVP zones could get a jump on you, you could also hide and get away. Maybe make safe zones for people who dont want to do that sort of thing, like road patrols so you can still implement quests, but then the wastes are PVP zones or something.
I mean I guess that's not the Fallout game fans would want but if youre gonna make it an MMO experience, you could do better. Even with Elder Scrolls, you could have tried to put in more of the open world experience the games are known for.