You're just too easy to make happy too, NiKr, I think.
I mean, I love idlers

I'm at the bottom of the foodchain when it comes to pleasing me with a game.
But as I said, OP is a heroin addict who somehow thinks there's something better out there, when there's not. SAO would add the only missing "dynamism" to the equation - the full immersion. A monitor and a kbm/controller can only take you so far. I mean, I guess there's the literal infinity of thought but some people can't access that freely, so D&D-type stuff doesn't apply.
For me a non-SAO peak mmo would be a game where you can create your own spells. I had an idea of an elemental particles-based system, where you start with pretty much a pixel of a single element and go as far as "combination of all elements into "a something" that draws upon the mana of everyone in a 500m radius around your character".
And as you pointed out, this kind of freedom of choice could be applied to other kinds of content in the game, but I can't even begin to imagine how difficult this type of game would be to design/develop, let alone balance.