Thanks to Chinese gaming media, we've got an idea of which adventure we're going to be seeing next from the Hearthstone team. It was revealed that the next theme will be a World of Warcraft raid that contains 3 Chinese characters.
This comes to us from a post on Tieba, the author previously leaked the Morgl hero before he was released so this has some weight to it.
Thanks to /u/czhihong on reddit for compiling a correct list of raids that are 3 Chinese characters in length. They are:
卡拉赞 Karazhan
奥杜尔 Ulduar
永春台 Terrace of Endless Spring
悬槌堡 Highmaul