Earlier quoted context omitted.
If starting from scratch, what would an MMO need to replicate that? I've experienced it first hand, but I can't grasp why it worked well like it did.
You’d need to start with the premise that combat shouldn’t necessarily be the focus of the game. Work on making other aspects (farming, hunting, taming animals, etc) to be equally compelling mechanics.
I'd go a step further, not just equally compelling, but it'd be interesting to see some games, particularly RPGs, where combat is effectively optional. One of many ways to level up your character and complete the objectives of the game.
There aren't many out there where you could have a complete pacifist playthrough, for example, and if there is, you usually still have to resort to theft, or use of paralyze & calm spells.
In most RPGs your professions (farming, herbalism, mining, etc.) are just secondary skills to help you progress in combat, and all the good stuff comes from killing enemies.