Well the big problem Shamus is that Bioware is pretty much into "do nothing" desicians that don't really influance much except maybe a sidequest here or there. No matter your desicians or moral compass all of the same basic events take place the exact same way.
People have this vision of games where you can make all of these meaningful desicians with equal, but differant content coming from each one, and the game winding up being entirely differant based on what you choose to say or do. Right now, no company has wanted to invest the time, effort, or resources into doing that, especially for a very long game. The technology for it exists, especially in games with a fairly sandbox approach to begin with, but nobody has really wanted to go there.
In the case of games like "Mass Effect" or "The Old Republic" your storyline isn't going to change much based on what you do. What's more there is a deliberate effort being made to prevent one path or another from giving an undue advantage. Being able to make fights easier by say blowing a minion or boss away during dialogue with one moral choice or another would make that desician advantageous and give you an advantage over someone who made the other desician.
Likewise you can pretty much guess that a dialogue desician that would change the purpose of the NPC or plot development (which is usually pretty shallow and predictable) isn't going to turn out that way. To be honest I think Bioware is screwing with people intentionally with the whole "what you pick, isn't what comes out of the guy's mouth" schtick.
To be honest though my big problem with Bioware is that I increasingly feel like a moron playing their games, since your character rarely picks up on the most obvious subtexts, asks the right questions, or presents reasonable, oftentimes obvious, alternative solutions to various problems. In general if you play the "bad" path you are pretty much going to kill people or do nasty things for da lulz, if you play the "good" path your going to be a frakking moron with no sense of scope. In a Bioware game your pretty much given an option where you for example either turn a superweapon you just recovered on the civilian population or let it rape a planet of all it's resources to fire, or destroy it right then and there... no middle ground, no thought for the long term, just one moronic all or nothing solution or the other, neither of which are going to change anything as far as what you do next is concerned.
Honestly a lot of this is why I'm becoming less enthused of all the cinematics and "fully voiced conversations" in games nowadays, I saw the potential in this, but it long ago ceased to move forward, and 90% of the people doing it can't even be bothered to have multiple main character voice tracks for the same plotline like Saint's Row 2/3 did, never mind actually making them mean anything, or even put any serious weight behind them because usually I wind up with a choice of two equally stupid or extreme things, neither of which I would do in that situation IRL.