I'm still hoping for this to be a thing in the near future, especially with the werewolf tease. Having more medieval/gothic era architecture clothing and armor would go well with most of the occul...
If they ever make a medieval pack, I think it would be lovely if they added also a medieval mode we can toggle in settings and which will replace all neighbourhood decor and buildings with medieval looking ones. It may not be possible for all neighbourhoods but I think for many it may work. This way we can fully immerse in the medieval gameplay without restricting it to just one neighbourhood like Batuu.