Dire Bare
Legend
In my campaign intro document, I have fewer than a dozen house rules. Those include no evil characters, play someone who wants to be part of a group, don't play chaotic stupid and a list of allowable races. There's also links to a ton of other information and history for the world. Along with more doco and history than even I can keep track of. There's a lot of history to the campaign world.
This is cool! If your campaign strays from a by-the-numbers standard D&D game, having a campaign "players' guide" is a great idea!
But no, I don't explain why I don't allow dragonborn or kenku or whatever race of the week comes up. They simply aren't part of my vision for my campaign world.
This, I think, is the heart of our disagreement. Or perhaps rather, our differing perspectives.
Without trying to stereotype your style as a DM, I'm seeing your perspective at one end of a spectrum . . . . your campaign world is a personal, almost literary creation, perhaps quite detailed. Your players are guests in your world, and perhaps can contribute to it's development during the game, but are not the primary developers of it, you are.
Dragonborn don't exist in your world, just as they don't exist in Tolkien's Middle-Earth. Should Tolkien have added half-dragon folk to Middle-Earth at the request of some of his readers? Of course not! (unless, he totally thought the idea sounded cool and got to work adding them in!) If I'm a DM running an "Adventures in Middle-Earth" game and wish to retain fidelity to Tolkien's vision, should I allow dragonborn in my table's version of Middle-Earth? I could . . . but I don't think too many folks would find it odd if I did not.
This style of campaign fits well with the "DM as God" style of play (don't mean that as a bad thing) . . . where the DM has sole (or primary) control over all aspects of the game and players can either play by the DM's rules or find another game more suited to their tastes.
I'm sitting at the other end of the spectrum (or at least, that's how I'm seeing it) . . . . I might spend hours of my personal time creating an elaborate campaign world for my players, but I don't see it's purpose as my own artistic creation, but rather as a canvas to collaboratively tell a story with my friends around the gaming table. I want them to have almost as much input into my world as I do, I want them to surprise me and help me take the game and story in directions I could not have predicted.
There are no dragonborn in my world . . . . yet. I just never got around to adding them in, didn't get excited about them. But I have a player who read about the race in the PHB and is really excited about playing one. I've got no idea how I want to incorporate dragonborn into my world, but I'm going to say "yes" to the player and we're going to figure it out together.
Which style is the "right" or "better" style? Neither, of course. Although, I certainly have my preference and try to avoid games that treat the campaign setting as the personal domain of the DM.
If I allow dragonborn, what's next? Kenku? Tabaxi? Loxodons? Shard Minds? Could I find a place in my world for warborn? I suppose I could. None has ever been around since the beginning of the campaign decades ago, but if nothing else there's always a shipwreck from a far off land or a rift to another plane of existence. But I would want a race of sentient constructs to be the start of or the result of an earth shaking event, not just a race of the week.
What's next? It sounds like you fear allowing one exotic race will just lead your campaign world down a slippery slope towards armageddon!
