So Larian have now commentated on the claims about "cut content" and things found through datamining. Specifically on Karlach, epilogues and the upper city, but also generally about why things are changed.
The upshot is that things that are just a bit broken will be patched, endings will be expanded in time, but huge swathes of the game that people claim were just removed aren't going to suddenly appear, because they never existed.
There's a datamining thread in this very forum that shows off how much was there. The real takeaway from this is that it's likely going to lead to another flare-up of angry Karlach fans in the near future (they're not upset that the ending isn't poignant enough), that Larian was making very questionable decisions if you take them at their word (cutting the epilogues because they were... too long?), and outright saying that there is no "cut content" just "content they didn't want to release." It's a PR piece, damage control because Reddit is getting very upset about things that may or may not have been actually cut, and the tone of the article is strikingly different to all their other Community Updates.
But like, Larian was never going to re-implement much of this short of outright doing a Definitive Edition and even then it'd be really limited. Most of this stuff is outright gone. Larian's made their money.
