Blizzard might pull some "chosen of the loa " prophecy to make them extra relevant. In fact they kinda did that in Shadows of the Horde with Vol'jin. Though it might come off as slightly mary sueish
Selfish opinion: I don't mind if Zandalari overtake the Darkspear because I prefer that flavor of Troll. They are the troll master race and Rastakhan is a bamf.
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It isn't an origin story, it'll be relevant to current events.