Out of these probably Talanji, though I would say the whole Zandalari story as a whole. Her character has been rather consistent and had a solid arc of knowing how much the Zandalari were in danger and then wanting to head out to search for the Horde. She also played the most active role where we actually see her engage in both politics and battles. Jaina in comparion doesn't even appear in Kul'Tiras at all after the introduction, it takes you to do all 3 zones to get her quest chain and then at the end finally save her. This makes the 3 Kul'Tiran zones feel more disjoined and less problematic storywise than the zones were for the Zandalari. Also they made Jaina way to powerful while Talanji is at least ''balanced'', its easier to relate to such a character.
Other than that I don't really like all the other stories. The faction war stuff is some of the worst they have done yet.