As we well know Neera's, Edwin's stories all tie into Red Wizards of Thay him being one, and her escaping them. My argument for why Thay be perfect is two-fold, one it been set up just as well as Neverwinter was with all the references to the places in Icewind Dale and later Neverwinter. Two, we already know the Red Wizards are immensely powerful organization who machinations few know and could imagine. We could easily go down the route of Neera story being wild mage, perhaps they crack it and are able to utilize chaos or perhaps with problems on Sword Coast they start causing problems in Thay.
Another reason we have had most biomes, snowy tundras and temperate areas even more hotter climes, but not actual desert places and Thay would be massively intriguing since different Sword Coast and Athlakata we know Red Wizards are both political and powerful, who knows perhaps they even hire the hero or heroine, perhaps they could be the ones in danger from even greater power.
Now for details I found on this site:http://www.realmshelps.net/faerun/thay/index.shtml
Best known for the crimson-robed Red Wizards who rule the land with an iron fist; Thay is a realm shrouded in mystery. Few outsiders have traveled extensively within its borders unless abducted and sold into a short life of slavery there: The Thayans who do talk about their homeland speak of it with such pride as to make most listeners doubt their amazing claims - were it not for the fact that these same rumors surface again and again from a dozen different sources.
The Thayans have endeavored constantly to expand their borders since they won their independence from Mulhorand in 922 DR. In fact, it was only twelve years after that momentous date that the Thayans launched their first invasion of Rashemen. The Thayans have been beaten back numerous times from both Aglarond and Rashemen, but though their armies failed to subjugate these realms, they still brought the Alaor, the Priador, the Sur and Umber vales, and the cities of the Wizards' Reach under Thay's control.
The borders of Thay have changed little since the conquest of the Wizards' Reach fifteen years ago. The Red Wizards keep their armies at home these days, while their merchants have spread throughout the lands of the Inner Sea, selling valuable magic items in well protected concessions and Thayan enclaves. Rivers of gold, goods, and slaves pour into the zulkirs' coffers from this expansion of Thayan trade. Szass Tam and his colleagues have come to understand that gold can conquer lands that resist swords and spells, and Thay's monopoly on the manufacture and sale of magic items might be the weapon that brings the Red Wizards dominion over all Faerûn.