Vashj and Kael'thas definitely have a more prominent effect throughout the expansion, and to most people, despite being mere underlings. You *felt* their presence more and saw it more.
I mean, in theory the build up the Illidan was cool and the build up to Black Temple was awesome, it just didn't pan out, sadly.
Haha, yes you did. Made it when I made this account long ago, maybe even before. Can't remember at this point haha.
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Like giving us a "This is what happened, this is when it happened, this is the coherent flow of it all".
Fill in plenty of gaps to help make things more cohesive and feel more "real" for some, but also to add depth and complexity to it.
The point of it being was that so many people play WoW but only know Warcraft lore in the bubble of... well WoW. That robs them of appreciation of it, and much like plenty of people didn't know about Illidan, or had reason to care for Illidan, I'd say that a WC4 would be a great addition to the game to help invest and build up what has happened. It's not like you can really just be like "scratch that all".
Illidan wasn't present into much later in the expansion. While this wasn't inherently bad, I think increasing presence is a good thing, and the "looming" feeling of him getting closer and closer and your encounter becoming impending is a cool aspect to have, we were just so far removed and out of touch from him for so long that when we got to that point we did not have that emotional investment in him, unless you played WC3/TFT.