I'm cautiously optimistic after that teaser. Never expected it to be as China-focused as the books, but it seems like they're keeping some of the core elements like the Cultural Revolution connection.
D&D rightfully get a ton of flak for how Game of Thrones ended, but the first several seasons of that show were amazing and I'm curious to see how they'll do when they're adapting a work that is completely finished and has a solid ending. They will know from the get-go which elements of the story end up being critical and which can be adjusted to make for a better adaptation.
No clue how they'll portray some of the stuff in book 3 visually, though.