I stopped and began thinking about male characters who'd died in every expansion. The main ones and not the side characters, you begin to go wait a minute.
If I am wrong, fine, but I have an uneasy feeling in my gut. I'll list the ones I know of that come to mind. If I miss any or anything like that, let me know, I'll conclude at the bottom. I don't know much about Classic and Burning Crusade, and again, I'm only thinking about heroes of the Horde or Alliance.
Warlords of Draenor Male Characters:
Ogrim Doomhammer
Prophet Velen
Vindicator Maraad
Draenor Female Characters:
None, not one main female character died.
Legion Male Characters:
King Varian Wrynn
Warchief Vol'jin
Highlord Tirion Fordring
Legion Female Characters:
Ysera (Later brought back by trading Malfurion.)
Battle For Azeroth Male Characters:
Durotan (Wod update)
Warchief Grommash Hellscream (Wod Update) "I don't know if we should count them or not tbh, but they are noted as deaths, so I put them here in case someone brought them up."
High Overlord Varok Saurfang
Final Notes:
So from the expansions I noted, I saw a trend that was kind of concerning. Obviously, they didn't kill anyone in Shadowlands, Dragonflight, or the current expansion. But this got me thinking about why female characters weren't dying off much. Going to put a note that now Jastor Gallywix died, but I think he was always meant to be treated more like a villain with Goblins.
And the only females I can remember dying both came back. Sylvanas has returned 3 times if you count her defeat at the raid. She died to Arthas came back, jumped off Ice Crown, came back, and then that. Ysera was the first legit death, but they sacrificed Malfurion or traded places so she could return. Like, I know it's weird, but if they kill Lor'themor Theorn in the next expansion..Wouldn't that be weird? I just hope I'm wrong about this and my friend worried me with nothing.