To make a good multi-player RPG, design concessions must be made on the single player side of the game. This is especially true for titles with a lot of interactive dialogue and/or narrative delivered via text. George Ziets and I have had this conversation many times over the last few years, and it always boils down to one simple truth. Reading is not a team sport.
If you don't make those concessions, you end up with sub-par multiplayer. As much as I love the Baldur's Gate series, the multi-player aspect took a lot of patience (putting it mildly), as the design focus of those titles was the single player experience.
I do believe you can create an awesome multi-player experience with dialogue and choice and consequence, in my mind it would require a very large budget. I'll let you guys decide what that may or may not mean.