I got a suggestion
Diplomatic Knowledge.
Go and meet every leader of every city and /talk with them. Same for horde and alliance so expect a lot of deaths.
Talk to Thrall
Talk to sylvannas
Talk to Carnie
Talk to Vol'jin
Talk to Lorthemar
Talk to Varian
Talk to Magin
Talk to Tyrande
Talk to High Tinkerer Mechagaogoga
Talk to Velen
Talk to Adal
Talk to Rorhin
Talk to Rexxar
Talk to Garrosh
Talk to Tirion
Talk to Jaina
And a lot more I was thinking every outpost it would take some time but would be awesome