Outland is the best continent in terms of design and lore. It masterfully blends medieval fantasy with sci-fi, with a dose of the post-apocalyptic to finish it off.
That said, I would agree TBC definitely didn’t do a good job in terms of story. However, my reasons for saying that probably differ from what most would argue. One thing that really bothered me was the “coincidence” that the draenei happened to crash-land on Azeroth of all places. What frustrated me even more, though, was the events of 2.4 and in particular the restoration of the Sunwell. So, no, I’m not all that bothered about Vashj and Kael’thas being “wasted”.
Perhaps even more controversially, I think vanilla was horrible for lore. Particularly the whitewashing of the night elves was and still is a huge gripe to me. It also represents the era of WoW lore where magic systems were kept intentionally vague. Which is not inherently bad - but in the case of a world like that of Warcraft’s, where magic is a daily occurrence and some mortal races are indeed even fully dependent on it, requires the writers to organize and develop its magic systems. Unfortunately, it took them ages to do this, which is why we have the mess we’re with now.
This should’ve been done in vanilla.
Frankly, the very beloved Metzen and his gang weren’t all that much of the great creative geniuses some people laud them to be. Warcraft tends to have concepts which seem appealing at first - certainly often are - but that’s mostly due to the visual rendition of those concepts. I mean, art & music team for the win, am I right? But the truth is those concepts are in reality quite shallow, with not much structure behind them. That’s why they are often painfully superficial, and why their ideas generally don’t translate all that well in-game.
Since this style of storytelling continues to this day, I’ll give a recent example to make my ramblings seem a bit less suspiciously confused void elf 
.
Let’s take G’huun.
Disgusting yet eerily fascinating aesthetics? Check. Entrenched in the lore? Check. Edgy powers in the form of blood magic? Check. An army of similarly spooky and well-designed followers? Check.
So now that we have an intriguing enemy to fight for raiders and people who don’t read quest texts, let’s look how this guy really holds up.
Aesthetics: ok, like I said before, that’s done consistently well.
Everything else: not so much.
G’huun’s problem isn’t necessarily that he was made up on the spot for BfA. His existence is sort of feasible. What is problematic is the incredible coincidence that another blood god happens to be located at the very place the exiled followers of the loa of blood end up at. Or what about the fact that there’s absolutely no reason for him to have a connection to blood? Sure, he’s an “experiment gone wrong”, but since it’s a titan experiment gone wrong, perhaps a connection to anima (oops, I’m not supposed to say that; sorry, Shadowlands designers, I swear I’m not trying to tie your hands!) would be more logical? But since it’s not there… why does he represent the red, mortal brand of blood? Y’Shaarj’s blood is purple; Yogg-Saron’s a light blue/green. Which Old God was used for these experiments?
Also: “G’huun’s unique biology potentially holds the answer to eliminating their threat.” No pay-off? Yeah, none.
I don’t think any of comments on WoW’s general storytelling are much of an unpopular opinion, but I think believing the blame partly lies on our dear Chris Metzen certainly does. It’s been consistently bad.
