This expansion, thus far, is filled to the brim with more lore than we can get our hands on. Possible Old God return, Illidan being a marysue master of fel and light and questioning allegiances make to be some great storytelling.
Unfortunately (and I wish this wasn't the case), Blizz's storytelling is very linear and predictable and it always has been. I love theories of where N'Zoth is, that Light's Heart could actually be KJ or that the Naaru are actually evil and the whole Illidan being the child of light and shadow is bs. but I'm almost positive that none of these things can come true.
Im not a super big fan of Illidan being a super holy warrior of light now, and wish ideas like above could be implemented but Blizz's storytelling will follow the same path as it always has.
The Lore team at Blizz is great, but lacks the depth, mystery and meaningful development that we can find in authors such as George RR Martin, Robert Jordan, RA Salvatore and beyond.
Warcraft characters seem to have an inherent lack of dynamic motives. My favourite example is the theory that Vol'jin made Sylvanas Warchief so that all eyes will be on her and she cannot get up to anything malevolent like she did while Garrosh was in power. This has turned out to not be the case. Blizz made this decision because Sylvanas is a character that people like and they know that people will fanboy and get a shock value out of it. This leaves us who enjoy the story to question why a suitable and honorable Warchief was killed off to be replaced by a dark and edgy rebel. We make up theories to justify the writing but in fact it comes down to "I bet people will be shocked when this happens."
In short, I hope the Blizz lore team can somehow really start pushing dynamic characters and storytelling that keeps us on the edge of the seat, instead of the very predictable route it seems to be taking.