Now that HOD is out, I can see that people are still complaining about no Winds of Winter.
I think that maybe a good way to get closure for the 25 plus key characters is to borrow from the Witcher (CDPR/Sapkowski). The path here is similar to what Western psychology/philosophy talk of, the path towards "Wholeness", finding oneself completely and living a better life, more attuned to what we really are. This is an insight of the psychologist Carl Rogers. Geralt becomes whole at the end of Blood and Wine, and so do his family/friends. A happy and logical ending.
So maybe fans can use their knowledge of all these characters- Jon Snow, Danyers, Jaime, and even villains like Cersei etc. and think of a logical and more positive ending for all of them, and be content with their own personal vision of how their story ends.
I am looking over the Blood and Fire wikia/book to see if there are clues on how GRRM would end ASOIAF. GRRM describes his style as the 'bittersweet' ending for the show. I disagree, I found his ending more bitter than sweet, but at the same time tinged with a small ray of hope. Bad characters get bad endings.
So far in Fire and Blood wikia he follows the same trend. This kind of ending is not for me.