It's one of the better written games out there...
Which says a lot more about the abysmal standard of writing of video games than it does about whether or not the writing in Mass Effect was any good. Hint: It wasn't.
there's just flat out no way that you can call the game terribly voiced.
Uh, male Shepard voice? Any of the non-major NPCs? Any of the alien characters? Keith David, Lance Henrickson, and Jennifer Hale were all fine, but the rest of the voice was pretty middling.
If you want a shooter, play a shooter. RPG's have dialog
I didn't say I wanted a shooter, I said I wanted better writing. For the record, I've played through the entire Ultima series, the Gold Box series, the Infinity engine games, both Fallouts, both Neverwinter Nights, Darklands, KotOR series, and a smattering of the Might and Magic and Wizardry series, so I think it's safe to say I know what an RPG is and can be called a fan of the genre. Oh and I played through Mass Effect too.
All that said, dialogue has to serve a purpose, otherwise it's boring. Dialogue becomes interesting when it is full of characterization, establishes dramatic tension or releases it, or advances the plot. If you're dialogue isn't actively DOING something, if every word doesn't serve some greater purpose, then the reader/viewer quickly loses interest. By and large, video game dialogue tends to exist just to advance the plot where the speakers are just interchangable mouth pieces for the player's next objective. With this in mind, video game dialogue needs to get to the fucking point so that the action of the story can move along. Ever heard the phrase "Brevity is the soul of wit"? That applies here. Hearing characters drone on and on with hackneyed, laughably bad lines is hardly an entertaining experience.
Bioware needs to either take an editor's pen to their script and slash the bloated dialogue to the bare essentials, or higher more talented writers who can actually come up with something interesting for the characters to say for all their lines, and not just a few.