Didn't even need to stretch it out really just make everything that happened in this last episode happen in 2 episodes and then use some of the extra time to wrap everything up fairly fast (30 minutes or so, which would give another hour. Could spend more time showing Danny struggling and succumbing to rage, to at least make some sense of what she did, focus on her an John a bit more, showing them breaking apart (and how it hurt her seriously), instead of just 1 scene where he rejects her sexually but says she'll always be her queen.
I mean nobody has every rejected her advances/sexually, in fact everyone has been fighting over her favor (or selling it) throughout the whole series. Could be she's just that shallow and if you say no to her, she burns a town down.
But whatever, there was no way to really make the end results work for a majority of people watching it, in 6 episodes, the biggest mistake was trying to wrap up the story in so few.
Depending on how the last episode goes maybe they can do an epilogue mini series for it. ---