And there is a reason why the story always fails to compare. It's inherrant in the concept. In a single player RPG, YOU are the hero. The one true prince apon whom the fate of the world hangs. In an MMO... you're a peon. You are part of the faceless hordes or guards, soldiers, and widows and orphans that that selfsame true prince wades his way through with his sword. Cause in a world where everybody is the one true prince, harbinger of doom, savior of the world, etc etc, then nobody is.
I really don't want to be a pessimist about Biowares offerings, but I swear we have heard this exact same rant about story driven MMO's given by virtually every MMO producer before their big release, for at least the past decade. I think UO and Everquest emphasized freedom and do what you want. Every other game promised to be much much more "story driven". Pretty much none of them succeeded at it. (Turbine and Blizzard have probably come closest). While I think Bioware has great intentions, and does a good story. It remains to be seen if this will work in a large scale MMO environment.
Personally I think that a story driven MMO is as much a pipe dream in a persistent world game as is the frequently chased after development snipe of "PvP with real consequences".