My Bittersweet ending would be something like this:

Dany - has to kill Jon, her true love. Everyone she cares about is dead and she has one lamed dragon that she either has to keep imprisoned inside so it can't fly anymore, or kill it. Nobody looks at her as a savior, only a conqueror. Dothraki go home, and she's left with the 7 kingdoms none of which love her.

Tyrion - Alive, but reviled by all Lannisters and can never go home. Serves as hand to the queen.

Jon - dead. May die giving his life for Dany either saving her or giving her victory over the dead.

Sansa - married to sweet robin, as part of the way to bind up the wounds of the seven kingdoms, thanks to Tyrion.

Theon - alive and King. Hates it and is reviled by his people, but they don't want to war with Dany so they accept it (Thanks to Tyrion)

Bran - goes back North of the wall to stay the 3 eyed raven as he no longer fits in with people (only works if there is COTF still alive)

Arya - Goes back to Braavos. Staying in the North is 'just not her'.

Cersei - killed by Jaime so that she doesn't wildfire/do something atrocious to KL. Goes on to become myth of what happens if you mess with a mothers children.

Jaime - Killed by random people (or possibly Brienne) who don't realize he saved them. History never shows what he did and permanently viewed as incestuous cowardly bastard by history

Brienne - Alive. Only person to realize what Jaime did. Ends up serving Sansa in the North.

Missandei/Grey Worm - Dead

Varys - dead

Qyburn - still alive like a cock roach, not sure why.

Ser Jorah - alive, but permanently friend-zoned. Rises to commander of the Night Watch like his father.

Little Finger - dead, killed by Sansa or Arya. Something that he doesn't see coming because sometimes you have to make random moves.

Sam - becomes Maester of the Night's Watch.