I agree that for a scientific city-state Sukothai would be the best option. At the same time I can still easily see a Thai city-state becoming either commercial, cultural or religious even more.I would probably prefer Sukothai. Between giving us a continental SE Asian CS and representing a past civ, it just feels right. Plus there are so few options for east asian science CSs and the Thai kingdoms seem like one of the only reasonable options (as opposed to cultural, commercial, religious, militaristic CSs for which there are still plenty of options...even industrial civs really given the recent economic surge in ASEAN and imo Yakutsk being a solid option.).