If you really want a really good MMORPG, with wide appeal, you want a diverse set of gamer types.
And if you want that, then each style needs to be created for good game play.
But the lowest common denominator removes good game play from such aspects as economy and exploration in order to make it "easy."
Easy FOR ALL players. Even those who aren't good at it and don't want to learn any tricks of the trade, etc. Don't want to spend the time and effort into learning the skills involved, which aren't always in code but rather in a player's personal abilities.
I think each aspect of game play needs to be made for players who actually enjoy the challenges of that particular sort of game play.
And not for everyone.
Otherwise, you get boring game play for those who care about those aspects. And that's not a recipe for keeping customers.