I have 2 reservations about Fallout 76 being a multiplayer game:
You wont be able to kill anyone important
Crazy OP builds will be nerfed to balance the game
To me, it's not Fallout if you can't walk up to a main character and blow their brains out with a mini-nuke because you felt like it (hence why Fallout 4 was the weakest of the series in my eyes)