They've done alright. I mean, they took a big chance on having EVERYTHING voiced-acted, as that makes it harder to change stuff later on and takes up huge amounts of disk space as compared to textual stuff.
Personally, i'd be far more happy if they actually made the choices you get in the dialogue options to match what it actually is your character says. Choosing something like "I can't agree with that" and having my guy actually say "Wow, you're a complete moron, aren't you" (and subsequently getting a dirty look from my companion) detracts far more from the 'story-driven' aspects so heavily advertised than any voice acting would.
That said, a friend of mine had a very good idea that I think might be doable for Bioware. The game already has it such that in some cases, such as certain helmets, etc., your character's voice takes on a slightly 'digitized' voice effect. That implies they can make those sorts of changes to the sound file on the fly, and that means it should be potentially possible for them to adjust the regular voice a little. Not a lot, of course, but it might be able to set the character voice for a character to be deeper or higher than the default voice as a result, allowing you to choose different 'versions' of the voice depending on your preference at character creation.