I disagree. Sure, your actions have got immediate consequences for later acts, like saving tieflings, etc. This is a good thing, it means the game is reactive to your choices.
However, you are comparing apples and oranges. Doing all the quests, sidequests, companion quests and never learning if your choices actually did anything long term is wrong for an rpg.
If I romance shadowheart as a good dark urge, I want to know if they are living together at the farm, stayed together or maybe not, based on the choices I have made.
This isnt even a matter of slideshow, but a proper epilogue for all the companions and the world itself. Be it interactive cutscene, slideshow or something else. I can make my own headcannon, sure, but the game just ending without proper goodbye is not a good thing no matter how you slice it.
First off, I re-read your first post and noticed that you haven’t actually got there yet. So either you’re complaining about something you haven’t actually experienced, or you’ve spoiled the ending(s) for yourself far more than Larian has. Hopefully the former.
So you don’t like me comparing how faction stories were resolved with FNV, how about companions? Not one companion in that game had a single word to say to me about what we did, or what’s next for them, let alone allow me to try to change their minds. It goes straight from a chat with the colonel, the robot or the dude in the silly mask to a couple of sentences telling me they parted ways and were miserable. Now I loved that game, but I wouldn’t say it handled ending better, just differently. It was an artistic choice to end that way, not a requirement.
You also mention the “outrage” if films ended like this, but most do. Very few have Return of the King style drawn out epilogues. And a quick bit of narration or text is generally reserved for historical stories, because there were real life events that happened after the story finished. In most other cases, the story ends and what happens after is not explained because it doesn’t need to be. Sometimes the end is ambiguous, sometimes it’s a cliffhanger, and they can work too.
My main point though, is all the people saying that choices don’t matter if the game doesn’t explicitly tell me that they matter. I helped the tieflings at the grove, I helped them again at the inn, I helped some of them yet again in the city and I checked on others to see how they were doing. That mattered to me in my playthrough and I don’t need Ron Perlman to tell me that it mattered.