I getcha, all ideas for a better outcome are good. Im just hoping that larian sees we want more then a few lines of dialogue at the end and cinematic in the long run.
Also i dont really think anything NEEDS to be added into acts one or 2. For karlach. I think if anything her added content should be after gortash fight. (That VA work after the fight is to good) something after that would be the most satisfying i think, right when she is at her lowest we find away to get her fixed either through avernus or gondians. But let it be IN GAME let us be able to pursue her questline and give it a proper ending.

I know the 6 month epilogue is the path of least resistance for the studio. But lets shoot for the stars here guys.
Even if it takes a year and no changes until a game of the year edition or DE. Id much rather larian goes all in rather then a bit of pokish abd call it a day.