It is and it ain't. If you go by the show (and I believe the book ending will follow the same broad strokes) you will see that from now on the king will be chosen by an election and that one of the most culturaly diverse areas of the realm is now independent. Also, a new culture has been integrated to Westeros (dothraki), a woman has notoriously became a knight, and so on and so forth. All those things stablish precedents for further democratization, further secession, and further social advancements.