For Essos to be orientalist, it would have to be basically analogous to traditional representations of actual countries in what was once called the Orient. It's not. Both the Valyrian subcontinent and Slaver's Bay, for example, owe much more to Rome than to any "Eastern" nations. The problem is that Martin's geography, ethnicities, and (sometimes) architecture create an East-West dichotomy like the one in the real world, so readers treat Meereen as an eastern society even though it's equally Roman. right down to the togas, er, tokars. I think he does that in the hope of undermining the perceived differences-- Dance
explicitly suggests similarities between Meereenese slavery are Westeros' feudal culture-- but the disinclination to write from and fully investigate the perspective of those characters make it feel more like an exercise in othering. Which is a better buzzword for this case than Orientalism, I suppose.
because it's a very different kind of show compared to those.
You'd have to elaborate on that. The only difference I can see is that one foregrounds its thematic ambitions in its recasting of popular genre material, and the other is content (like, it must be said, the books themselves) to shape itself as a plot-driven entertainment.
It's difficult for me to see how the show wouldn't be improved if, for example, it had reproduced the complex, strategically smart Catelyn of the books, a non-traditional fantasy female character who represents a voice of reason and peace to contrast her son's adolescent pride and war fever, rather than turning her into a generic wistful mom-figure. Or if it had featured Arya's decline into a cruel, childish brutality, rather than keeping her the delightful fantasy tomboy. Maybe it'll still do the latter, but I have my doubts. Padding out the Olenna scenes because they got Diana Rigg is nice, but it doesn't amount to anything on dramatic terms.