I really enjoyed my ending that I got on my first playthrough! True, I reached the ending already with patch 5, when the party was added to the ending, so the experience was great. The final scene at the docks just filled with a feeling of joy, elation, real victory. After the party there was a desire to go back to the game, which is very rare for me, usually, if I go through some particularly interesting games more than once, I always take a break for another game to forget a little bit of the story and avoid the feeling of repeating the same thing. But not in the case of BG3! Though I can see why, with certain choices or having a special affection for certain companions, a good ending can feel like a tragic ending to the player. In my case, all the companions were fine, only Karlach became an illithid. But I agree with neprostoman, she ends up being very positive about her experience as a mind flayer, even saying she wouldn't have chosen a different fate. Everyone else was happy and shared their stories with me at the party:
The Ascended Astarion at the docks cheerfully offered to celebrate the victory at the tavern, then a romantic epilogue, an adorable bat at the party, the Lord's lovely costume, all in all a sunny finale to “Aeterna Amantes”. <3
Shadowheart has chosen Selune, is traveling the world, received owlbear as a gift. Seems peaceful and happy to see everyone.
Lae'zel went with Prince Orpheus to liberate her people. She couldn't come to the party because she was busy (of course, she seemed to be the chief diplomat of the githyanki now, and was holding important negotiations), so we talked through the projection. She looked solid and competent.
Gale got rid of his problem, became a professor, came with Tara and talked about negligent students.
Will has chosen the path of blade of avernus, is hunting for Mizora, and is eager to talk about his exploits (only one of the three, though, and I have to restart to hear about all of them, which is weird, I mean, it's not like we're going anywhere in a hurry).
Halsin opened an orphanage for children, which he was happy to talk about, and donated a wooden duck.
Jaheira made me glad that she's leaving Baldur, probably to seek adventure (and that's great, there will be less annoying neighbors in town).
Minsc brought some poor halfling, whom he had been mocking before, and, as usual, was talking some nonsense in his own style. The halfling sort of slowly recovered from the stress, and started drinking and snacking at the common table.
Unfortunately, in the first playthrough I missed Minthara, because I played without spoilers until Act 3, at the first encounter I took her for a regular boss, and I didn't pay enough attention to the fact that camp clothes are not looted from regular bosses. But she made the next playthrough more interesting for me, because a new companion, whom I was not familiar with before, will diversify the game quite well.
I don't perceive my ending as miserable at any point, but if Larian improves something about it at the request of other players, why not? Maybe I too would take advantage of that improvement in another playthrough. The story itself requires someone to become an Illithid anyway (well, or an alliance with the Emperor who already is), this can hardly be changed in any way. The Gortash-illithid option is an interesting one, but it looks too time-consuming to implement when the Larian are already finalizing game development. Plus, the alliance with Gortash that would be required to do this removes the player's ability to save Will's father, and would still result in one of the companions being upset (if you view this method as the key to making everything perfect for all companions).
I voted for option 4 because I'm happy with everything, but I'll never be against any change for the better. Option 5 is so fun that it's impossible to resist from voting for something, just for the sake of looking at the stats and seeing how many players chose that option.
