Meh, this is basically my problem with voiced protags. It worked with the Witcher, mostly because there was a backstory of books that you could look up for extra padding and stuff.
But ME style? It worked for the first game, mostly because they kept the closest to their Open Palm/Closed Fist morality system they've EVER kept to that they'd been trying to make work for years. 2 and 3 however just dropped that for their normal schitck that's kept through in that You're either Cyborg Hitler(literally) or Clean Soul McGee.
And I'll say it forever, Origins had the best conversation choices in YEARS if in nothing else but the variety of answers you could give(also I find it funny that some people in here are complaining about the silent pc being a box when they were also talking down to the guy that made the "Witcher is proof that established voiced protags are the way to go" and saying he was too lazy to roleplay) that gave you the freedom to do one of three choices essentially, but the personality of your character gave each of them a different meaning if you bothered to make that part of them up.
Personally I'm just not seeing a huge amount of pros to the voiced protag system in this case. It chucks a huge amount of roleplaying options out the window(their voice you make up, limits your character creation because there's a voice that will NOT match anything you make but the default and the novelty of an ugly-tree busted Asian guy in clown make-up with an Iowa whiteboy voice wears off REALLY fast), just basic camera angles are probably going to be focused on your face so you can't really implement the text-only thing you're talking about without people then complaining it's doing the Origins thing(which would be my only problem with it, too much time focused on a random dude looking around silently) and the game is going to have to have to MASSIVE considering it's going to have at least three times the voiced lines unless they do a bunch of generic answers simply because they have a voiced protagonist in addition to all the NPC's that have to talk to you.
Honestly overall though, just not looking forward to the Mass Effect wheel becoming standard, because it's so damned flawed the way it's evolved from a wheel of dialogue into the wheel of morality. Not to mention it rarely ever tells you what you're actually going to say.