I thought I'd post this here. There is very little (read none) chance of me ever doing this mod but here is the idea...
All mod npc's come with soundsets and voiced lines for major quest/interjection dialogues.
How about a mod that attempts to add new soundsets for the same type of dialogues for the PC? We take the core soundsets plus major quest/storyline/interjection dialogues and possibly some banters and do new voicing that the PC can use.
Yes BG2 comes with a set of stock voicing but is this quality, suitable or even enough? I imported the PST soundsets a long time ago and tend to use one of these for my PC.
It might take some work and a lot of voice actors but it might be worth it...whether it would add anything to the game for players is for you to decide!