The world building of Westeros is not really the strong suite of the show. Beyond Winterfell and the North, the Wall, Beyond the Wall, the Riverlands, King's Landing, Dorne, the Iron Islands, and Slaver's Bay we do not really get a good sense for much of the geography. Cripes, until like yesterday I thought the Stormlands were *north* of King's Landing. The Stormlands, the Vale, and the Reach are all incredibly underdeveloped in the show as far as I remember.
No, I think it would be much better to have a show that tries to capture the same spirit as Game of Thrones had before it literally went off book but set in a part of the world where Westeros is peripheral. You can have recognizable elements of Westeros in Essos, the same way you have Melisandre, Syrio Forel, the Iron Bank, and others involved in Westeros. We are living in a cultural moment here and more of the same with a cast that mostly looks the same would be a huge mistake.