Do you have an answer to Xoth's question: If the Bard is reskinned as the Shaman, what would you reskin the Druid as?
I mean, Xoth obviously prefers to "activate" both classes.
While I agree Bard > Shaman makes a certain sense, the advantage of Bard > Courtier (which certainly makes sense as well) is that you can have a role for the Druid too (even if I agree the Shaman isn't a perfect fit for a D&D Druid).
Note, the Xoth pdf says there is no Bard class in the setting, and the Druid serves as a shaman. In this case, drop the Druid and use the Bard instead for the shaman. College of Lore is a decent choice of a Bard for a wiseone of a ‘Savage’ or ‘Nomadic’ indigenous community.
Keep in mind, the 5e Bard is a full caster and might be too magical for most kinds of courtiers. The Xoth pdf creates a new semi-magic class called a Courtier, including the Seducer subclass, that seems to me a reasonable amount of magic for this kind of character concept.
If there is some kind of powerfully magical leader or courtier, yeah, use a Bard here too. The College of Whispers seems great for ‘Decadent’, and a maybe a College of Swords for ‘Civilized’.
With regard to the Druid, reskin it as a kind of courtly alchemist in an ‘Enlightened’ technologically sophisticated culture. It can make sense that a powerful noble of a powerful city-state, would patron someone who knows the secrets of a flashy magic. And this courtly Druid might have apprentices who go on errands (to find ingredients, uncover magical secrets, test magical skills, or so on), who might be player characters. These Druids would be rare, but they would know who each other are.
There is no Wizard or Sorcerer. So the Druid and the Warlock are the two ‘high magic’ classes of the urbanized cultures. It can be interesting if their flavors contrast each other.
This is where the Warlock class fits in:
"Magic is generally feared, and most magicians are associated with dark curses, evil gods and unbearable secrets which «Man Was Not Meant To Know»."
This is where the Druid class can fit in:
"(but not all)"
The Druid can be more in tune with the processes of nature, perhaps even in a protoscientific way, whereas the Warlock is more in violation of nature.
In any case, this is true for both Warlock and Druid:
"The select few who are able to use magic and cast spells guard their secrets jealously and attempt to use it to their advantage, often to the detriment of others, and sometimes also to themselves."