We need a dragon based x-pack at some point maybe after Kul'tiras - In Kul'tiras we should discover the void as a threat but unable to fight it directly yet.
Elemental was heavily represented in Cataclysm I love elementals though so we should have another one , demon-based xpacks are done.
Titan based is close second, and third the Nerubian based dark below, when we start fighting the void. And then take this fight beyond to the void dimension itself.
I didn't find the right solution from the internet.
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