Apparently I need ‘A Nation United’ so I can unlock Kul Tirans but the useless achievements panel doesn’t actually tell me what I’m supposed to do to unlock it. I’ve got Loremaster of Kul Tiras, and Pride of Kul Tiras but A Nation United is still needed.
A Nation United…
So, you get Pride of Kul Tiras from the Jaina Questline, you then have to do Seige of Boralus. After completing that dungeon you are given a quest by Genn Greymane called “A Nation United” which is to attend a council meeting at Proudmore Keep. Once you do that and hand it in, you get the acheivement “A Nation United”.
Note: This used to require Mythic Seige of Boralus, but now only requires Heroic so you can queue for it in the finder. I am sure there will be quite a few queueing for that today
You have the Pride of Kul Tiras achievement. When you hand in the quest that grants you that achievement, Talia flies in saying that Boralus is under attack and you are given a quest to do Seige of Boralus.
Perhaps you handed in and left before Talia arrived? Go back to Proudmoore keep and see if any quests pop up there, I think it was outside in the gardens somewhere, near where the family grave was if I recall correctly.