Bought Civ V on sale a long time ago. Like anyone else who is a fan of the Civ series, I hated it immensely. Vanilla Civ V is so dumbed down and emaciated content wise compared to previous entries in the series, that its like a bad joke.
I don't know how it happened; but this expansion makes Civ V enjoyable
if you're familiar with Civ V's criticism as the game being intentionally released unfinished and selling off what should have been core features later on as DLC; that's exactly what BNW is..