My opinion? For Fallout to have a voiced protagonist, it needs to make the dialogue a lot clearer than "SARCASTIC, YES, NO, INFO." Maybe "Yes, I'm very interested in getting chewed apart by deathclaws." "I'll do it." "Nah, not interested." "What can you tell me about what I'm supposed to do?" instead.
Again, I think we should have multiple voices for each gender. The male can have Troy Baker, the guy who voiced Caesar, Erik Todd Dellums and Ross Scott (not a VA, but he'd be great at it) and the female can have Felicia Day, Amanda Tapping, the one we've got right now, and maybe someone a little older sounding.
I kinda want Obsidian to do a zany, weird DLC for F4. The reward for completing it would be a chance to sign up for the beta of New Vegas 2 and some Courier's Stash-style exclusive DLC for it.