On a global scale, is Westeros any more than just a remote backwater of no real consequence? It seems like all the Essosi think of Westerosi as savages, the Free Cities are more advanced, and every time a foreign power like the Andals, Rhoynar, or Targaryens, they always seem to win.

I think that’s stating it a bit too strongly – what with Argilac and Aegon intervening successfully during the wars against Valyria, and the conflicts between Prince Daemon and the Triarchy, there certainly are other cases where Westeros has been influential in Essosi politics.

So I would use an analogy as similar to Russia compared to Western Europe throughout much of the early modern period: somewhat on the edge of “civilization,” technologically somewhat behind the times, but with immense population and natural resources still important both in terms of economics and geopolitics.