I was thinking about this lately and very few major heroes in WoW ever get killed off. I’m going to clarify real quick, when I say heroes, I mean they die AS heroes, not them getting hit with corruption or a villain bat. I specify this because this way of killing of characters (Kael’thas, Lady Vashj, Staghelm, Benedictus, Nazgrim, Ursoc, Ra-den, etc.) because it has long been criticized on the WoW forums as being cheap and often seen more as annoying rather than tragic or otherwise impactful (main exception being Ysera).
Up to WotLK, pretty much the only death that I can think of was Dranosh Saurfang, In Cata we lost Cairne and Krasus in the books, Rhonin in the pre-patch for MoP, Maraad and Taylor in WoD, a 3-in-1 with Varian, Vol’Jin, and Tirion during Legion (and debatably Ysera, but that could fall under corruption), Varok Saurfang and Rastakhan in BfA, and nobody in Shadowlands or Dragonflight (so far).
Dranosh was a Horde character, Cairne, Krasus, and Rhonin were all book-deaths (with Krasus and Rhonin only being major players in the books), Maraad was mostly just an Alliance character whose relevance was in the comics, Taylor immediately came back as a ghost garrison follower, Vol’Jin is reincarnating, Ysera seems to be coming back, and Rastakhan was only onscreen for 8.0 and died 8.1.
In terms of deaths that would likely have an emotional impact on players of both factions, that leaves Cairne, Varian, and Tirion as characters who died as heroes, not as quest fodder or loot pinatas. Of these, Tirion was literally ONLY brought back to show up and die; if you count the Ret scenario we essentially watch the guy die on-screen twice (which was always weird to me).
I’m not saying we should start pulling a GoT or TWD here, but we keep adding more relevant characters who barely have any screen time (the Forsaken have a council of 4 guys of which I only recognized 2, the Pandaren leaders STILL have almost no relevance, and half the Allied Race leaders went offscreen as soon as they joined) without killing off characters unless we need a new raid boss. The Jailer literally took Thrall, Jaina, Baine, and Anduin and they ALL survived; surely, we should have lost SOMEONE there, right?
It makes it hard to feel like there are stakes when the only people dying are side characters or nameless off-screen masses. In Legion, outside of the Broken Shore (literally the first 30 mins), the stakes were pretty non-existent as far as the Burning Legion went (you could argue Ysera, but that was mort Xavius/N’Zoth than the Legion). In lore they were throwing the world into chaos, but from our perspective there were barely any other casualties AND we beat them on their home turf without losing anyone else.