I think (hope) they did this so they can have a larger variety of voices during gameplay, at the expense of full character conversation. The way it affects resourcing, they can afford to have 20 different character voices with a few dozen flavour lines whilst you're in the game world for less than the price of a single voice actor recording an entire game's worth of every character conversation choice. I'd prefer the latter too, but I understand the decision.
Once again I will address this since I have done so a lot in my thread. VA work is not that expensive if they are not well known names etc. They go by the day (avg pay is 200-300/day). Kind of curious, how many lines do you think they can get through in an 8 hour day? Answer, quite a few. So it is not a resource issue. Not to mention, the VAs are video recorded while doing their lines, so that their facial gestures are then imported in, that is the reason why the companions facial gestures are so natural. Before you say it, this is not an expensive process. It is actually more time consuming to do keyframe animations (as the PC is done now) than facial translation. It also is not as high a quality, that is why the player character's facial animations look so terrible.
Its not 2000 anymore, there isn't that large of a cost factor for doing VA work unless your hiring like Mark Hamil or something.
