Unhappy endings might be good indeed.
But there has to be some ending, that feels like proper ending.
For one I loved my ending in Dragon Age: Origins. I died slaying the archdemon. Hardly happy ending, but I was so very happy with it. It was just fitting and left a very strong impression in me.
And another Bioware example. Dragon Age Inquisition. For the proper ending I consider the ending of Tresspasser. I will try to avoid possible spoilers, but especially if player romanced Solas, the ending was definitely not happy, very much bittersweet. But that left also such a strong impression on me. (Yes I know Bioware has a lot of flaws, but these two endings really made me 'feel something')
With DAI it was very open ending to make a place for future games. So if Larian wanted to leave the end 'open', it might have been done much better.
BG III is one of the best games I have ever played, but the ending left me with feeling of dissatisfaction and just: 'That's it?'
As Sven said in some interwiev, they did cut the ending, because they thought that people would think it too long. So I genuinely hope they will add something in future. Beside this unsatisfactory companions ending, what about the rest of my choices through the game? I would really love these ending slides like in some other games, to summarize what my character achieved and what did come up of my choices and deeds.