The only way I would like to see multiplayer online from now on is allowing a massive sprawling world, in which you are presented with millions of quests, only some of which are repeatable, and if they aren't repeatable, only one person from the player base can complete them, and then they are taken offline.
Yes, I know it would never get made, but it would also be more realistic. Worlds where there is only one true saviour of the world, rather than four thousand who all save the world at different times, suggesting that whoever saved it first did a really bad job if it needed saving again when annoying 14yo number two came along.