I don't think they gave much thought at all to the endings. Its fairly obvious more was planned and got cut short in the later stages of development so what we end up with is basically a travesty of an ending that makes little narrative sense. All the characters suffer from this but it seem to me that even for Karlach (horrible though her endings are and I am not excusing that at all) the writers at least tried to make it seem as if her friends care. Whereas for Unascended Astarion he just beomes a joke, and that infuriates me. People simply don't behave like that, esp a team that has fought alongside him since the beginning of the game, they may not like him individually but they wouldn't make fun of him. It's squaddie humour (barracks humour maybe if not in the UK) but this group aren't an army unit and this type of comic relief is out of place in this setting and this story and it should never be a final scene in any setting.