Lore
While the Arathi Highlands has… not the most engaging questlines, it is a very interesting zone in terms of lore.
Before the first Human kingdoms were established, the Humans lived in tribes after being banished from their former Vrykul kin. Thoradin unified the tribes and created the first Human empire, the Arathorian Empire and the first city, Strom, was built. This was not welcomed by their Troll neighbours, and the first Human empire was led in a war against them, the Troll Wars. The Humans allied themselves with the High Elves of Quel’thalas for the duration of the war, and the Humans were taught the basics of magic by the Elves.
After a decisive victory for the Elves and Humans, their attention turned inwards: Thoradin explored the northern parts of the Eastern Kingdoms to find out more about the history of humanity. However, the immense power of Arathor was not long-lived: many Humans left Strom to establish new kingdoms, including Dalaran, Kul Tiras and later also Stormwind and Lordaeron. The power would slowly shift to Lordaeron and Stormwind. Arathor renamed itself to Stromgarde, named after Strom, and the whole Arathi Highlands became part of that kingdom.
The kingdom was still powerful, and with their location near the water, it became an important harbor. When the Second War arrived, and the Seven Kingdoms united in the Alliance of Lordaeron, Stromgarde sent a lot of help to defeat the Orcs. Following their defeat, Stromgarde housed at least one group of Orcs in the internment camp of Hammerfall.
However, the Third War did not go well. Nearly all Human kingdoms were destroyed, including the powerful Lordaeron. After Archimonde was defeated at Mount Hyjal, the power of the kingdoms shifted to the newly established Theramore and the rebuilt Stormwind. Stromgarde still existed, thanks to their remote location and Thoradin’s Wall, and was nearly untouched by the Scourge. However, Stromgarde was unable to keep itself standing for long without any of the northern kingdoms to trade with, and internal problems such as Galen murdering his father, Thoras, to become king himself. This instability resulted in the Syndicate and the Boulderfist Ogres to take most of the kingdom, including the city of Stromgarde itself. The remaining Humans created the League of Arathor, and dreamed of rebuilding their kingdom one day.
The Arathi Highlands became a sandbox for other races, and the Orcs from Hammerfall turned their former prison into a town. The Forsaken, who had allied themselves with the Horde, entered the kingdom from the west. Both Forsaken and Orcs expanded to the south, and occupied Go’shek Farm. The Forsaken started experimenting here to create the New Plague, and the Orcs used the farm as a source for food for Hammerfall.
Go’shek Farm reflects the rest of the Arathi Highlands. Abandoned and desolate, but with a rich history. He who visits Stromgarde would see that the city is destroyed, with only a few Stromgardian guards still walking around.
However, the League of Arathor had not fought their last battle: during the Blood War, King Anduin Wrynn ordered the Alliance to rebuild Stromgarde and the surrounding towns and farms. The Horde responded by building Ar’gorok, and attempted to attack Stromgarde. The Kingdom of Stromgarde has become part of the Alliance again, and is currently lead by Danath Trollbane, a cousin of Galen (who was slain by the Ebon Blade).
I know, it’s a lot, but if you talk about the Arathi Highlands and Stromgarde, you cannot ignore the rest of the history that took place here. In my opinion, the Humans have a very interesting history (up to and including the Third War, I don’t care much about Stormwind) and the Arathi Highlands greatly show that Humanity was once the very center of the world.