I don’t think Humans in Warcraft are exactly ran in a Feudalistic fashion, Stormwind is an Absolute Monarchy, this is true, but beneath that things are a bit more fluid, you have the regional capitals of areas ran by mayors and magistrates, neither of which can hold Vassals, which is a key element of Feudalism, nor can they hold a Fief, which is another. I mean sure, the wealthy or titled would have some power, but its not like anyone owns any land in the Kingdom of Stormwind, bar one man. Anduin Wrynn. -Nobody- else owns land. I am aware this may cause distress to people in Duskwood, but it simply is the case. People may oversee it, but they’re not even Vassals to Anduin in the classical sense, because in the main they hold titles that they are -elected- to. A Mayor is elected, a Magistrate is appointed, these are not hereditary or even necessarily life long positions.
The Kingdom of Stormwind, or Kingdom of Azeroth if you rather, is a rather bizarre blend of an Absolute Monarchy and a Constitutional Monarchy.
Now that doesn’t stop an individual nobleman/woman from having a retinue, or a warband, retainers to their service. It does however mean that they own diddly squat in terms of land. The King owns it. All of it. You might live there, but at his sufferance.
Same is true of Quel’thalas. Lor’themar Theron owns all of it, every last inch, doesn’t matter how noble your character is, you do not own so much as a scrap of land. Lor’themar is a (mostly) Benevolent Autocrat. If you are given stewardship of an area of land, that does not entitle you to restrict people’s passage, unless it is an active military facility, in which case take it to a raid so that you -can- restrict who comes in.
Equally Durotar, No one owns Grommash Hold, no One Owns Razor Hill, or the Barracks, or the Valley of Spirits, no one apart from the current Warchief. No one has ‘word from Sylvanas’ allowing them to do so.
I don’t actually think there -is- any player character Feudal society in the game…