i just had a kind of thought that when you think about it, one random subject kind of underexplored in fantasy is nationalism. the elder scrolls is the only series i know where /nationalist/ sentiment, as distinct from, eg. just fantasy racism, specifically plays a significant plot role
Was going to say that that's because it's anachronistic for most medieval fantasy, but then I realised that most medieval fantasy doesn't really deal with how bizarrely complicated the networks of fealty in medieval politics get and gives most characters a very modern mindset, so it's a fair point.
Game of Thrones does I would say. Youβve got the overarching imperialism with suppressed national identities of the kingdoms underneath that seem to be based as much on areas as dynasties. Then youβve got the free folk beyond the wall, the city states, and the Dothraki steppe warrior tribes etc
even the witcher is ironically never particularly interested in nationalism - there are hardly any characters that feel a distinct loyalty specifically to their country as a key motivation of their actions
In general I think the early modern period has a bunch of under-explored fantasy dynamics. The Reformation or the transition to absolute monarchies are interesting dynamics to use in a fantasy setting. Or the emergence of large armies.