The idea is good!!
I don't think I'll play this game if that's only the difference between it and the traditional MMOs, but I can see how that does male it feel more unique & immersive.
While it can be hard to pull the Morality part off.
I believe the other idea is great... There are many heroes each one works for their one universe and they meet at one point of the multiverse.
It'll be hard to make it feel "Massively Multiplayer" with only the player doing their missions alone. But if done correctly, player will never notice the gameplay parts of the story because it's so epic!!
if you have a story, a million people are gonna play it and they will SEE other people playing it.
Because the epicness value always gets lower when you see that L33T finishes your story before you do!!
You're not gonna play my game!? Ouch.
Well, fear not, you would be able to bring other players to your world with you. It's just it would not automatically happen. Guild Wars 2 actually pretty much already does this though it is not really given much of a story explanation.
Hey! It's not personal... I'm just not into MMO's (also MOBA games) or any game that requires constant internet connection and/or a lot of interacting with other players.
This idea is good, I didn't have that impression when I first read your post.
Hehe, I was just kidding, no hard feelings, yo.
Yeah, heh, I didn't really make that part clear in the post did i?