Skoll Shorties

Depends on if we're solely talking on their cinematics or their entire endings. BfA's Cinematic ending is byfar the worst considering how quickly it ends but the quests following after it made it better at least. WoD's is very much... well WoD.

Ending as a whole, final patch, raid, cinematic, and expansion wrap up. 8.3 felt rushed and out of place but the rest of the expansion was good in my opinion

Warlords of Draenor has to take it then, unfortunately. Archimonde's death remains confusing on whether he's gone for good or not. People suddenly forgive Grom for his actions with no consequence at all. No proper goodbyes are done after the raid. WoD just ends too abruptly.

That isn't to say BfA suffers the same issues. It does. But I personally really enjoyed the epilogue endings that each faction got. Disbanding the Warchief is one of the best things they've done in the lore.

Also, I know a lot of people are gonna throw their shit but both Argus and Archimonde were hardly built up as the final bosses of the expansion. At the very least N'zoth had since 8.1.5 to build up as the final antagonist. It still felt rushed but it was better than those two.