I posted a thread talking about the real life cultural basis of the playable races, but I posted in a Geno-OT thread talking about the real life cultural influences on vibes I got from the human kingdoms and decided it was interesting enough of a topic to make a thread on.
I've always got a Medieval France vibe from Stormwind, just in terms of architecture. While Gilneas is based on Victorian England with a Gothic architectural design. Dalaran is obviously pretty Persian in terms of architecture.
I don't really know that much about Kul Tiras, Alterac, Lordaeron and Stromgarde, but I've always thought if Blizz were to implement Kul Tiras in-game, it would be cool if it had a Venetian vibe.