In a day and age in which so many games are tacking on multiplayer just so that they can have another bullet point on the box, I can confidently say I can get behind Mass Effect's decision to go multiplayer.
Disclaimer: I have only ever dabbled in the opening act of Mass Effect 2, which I fully intend to return to and finish...sometime in the future. I know, blasphemy.
If anything, Bioware have succeeded in creating a world with the Mass Effect series: they've taken the idea of player choice, and while things are just about as binary as they get (you get to be the good guy or the bad guy, and that's about it - but that's fine, a space opera is better suited to that, this isn't nearly as gritty or dark as The Witcher or something), those choices have meaning and weight behind them. Because of stuff i did in Mass Effect 1, I might have an entirely different experience to my friend in Mass Effect 3.
That right there is the strength of videogames as an interactive medium. Bioware get that.
The Multiplayer seems to just be an extension of that; the world gets bigger and the experience that much larger. They're being purposefully vague on just how much it affects the Singleplayer experience, but that the two are connected in any way at all is probably going to be groundbreaking...more power to 'em.
