I am of he opinion that Larian trying to truly fix the main story would be prohibitively difficult and frankly, a dumb thing for the to try and do because of the amount of time, effort and money it would require. I happen to believe that the whole main story is bad right from the start, the problems begin in act 1 but you can't see how they'll truly crash and burn until around act 3. The main story is made on a bed of sand and fixing it would require changes from as early as the opening cinematic.
I also don't think Larian trying to fix anything is going to be helpful. They delivered this shambles of a story to begin with, why would they do significantly better when having to work around the dregs of what they've already done? I just don't think Larian has it in them to put out a better story. More time or money wouldn't have helped, I just dot think they have good storytelling instincts, not for this sort of thing. If you're looking for a strong, engaging main storyline then look elsewhere. If you're looking to spend ime with lots of engaging characters and see their stories, that's the part Larian seems to be good at. And good for them, that's a valuable skill. Maybe they'll len into that for their next game.