I think the "good guys" have taken quite a pounding, don't you? Seems like anyone with an ounce of moral fiber or goodness in their heart is a feast for crows, pardon the pun, and have been mercilessly slaughtered for the better part of 5 large books. The pendulum must swing at some point, or there will be little point to the story except "the bad guys win because they are BAD!"
After all, Hitler eventually did lose the war, but only after the good guys paid a horrific price. THAT is far more real than anything you find in GRRMs books. I'd hardly call the aftermath of WW II a "Hollywood ending".
Now to get silly:
Besides, everybody knows that Sansa is going to marry Aegon, find Rickon and put him back at Winterfell, rebuild Westeros, and usher in a 100 years of peace and plenty. After every last Lannister is killed by the King's Hand, Arya Stark, accompanied by her big, nasty direwolf, Nymeria.
Daenarys will scour the world and kill all the slavers with dragonfire.
Also, the Greatsword Ice will be reforged and given into Rickon's hand by Aegon himself.
Oh yeah. Jon Snow will wake up from his "death", marry Daenarys, and the two of them will take care of the Others.
Bran will become a mighty fine tree.
Tyrion will finally find true love.