You do realize how much extra dialogue was in Skyrim? I don't think it would be hard for them to get rid of NPCs who keep repeating the same meaningless crap over and over and giving your character some dialogue would be a problem. And I'm sure there are plenty of Fallout fans who want it, maybe not on the forums but in general who would want to actually hear there character talking. So it wouldn't be pointless, simply because YOU don't want it. Not everybody role plays I'm sure most people don't, so I'm sure there not going to care what there character sounds like as long as the voice actor isn't complete crap. And for people who like to role play and don't like the voice of the voice actor there could be a option to turn your character voice off. So the dialogue would be the way it was in the past fallout games were you don't have to hear your character speaking and it would be instantly as you choose your dialogue. As long as the developers can implement it well they should go for it.
Maybe not on the forums but in general I'm sure well over plenty of people want to actually hear there character talking.
There's no way either of us would know for sure, but it stands to reason that it is not going to impact sales positively when Oblivion, Fallout 3, New Vegas, and Skyrim are all insanely successful without it. Point is, it's not something that has been proven a necessary change for the sake of people's enjoyment. And I'm all for having options, but as the great Josh Sawyer has said, it shouldn't become Options: The Game. There's a degree of freedom that should be given to us, but this is the perfect example of what shouldn't be implemented just because some want it. It takes a significant amount of time, money, and resources to add a voice, and with the considerable amount of dialogue that the player character is involved in (about 99 percent of dialogue involves the PC) and the number of conversations in New Vegas especially, it would be a large investment for something superfluous. I have a hard time believing that such an option could be added without reducing the depth of conversation we've come to expect.