As suggested by the Crowfall twitter account, I am here to present a suggestion about allowing perhaps another race(s) to become Duelists or a gun related major discipline. Putting aside any personal likes or dislikes about having race unique classes my main thought is this. Why have the Guineceans not shared their gun technology with other races? Surely some of them are allied with other races via a god or via the broader categories of order, balance and chaos; or perhaps even within a guild? I think it is a neat and unique idea to have the Guineceans develop the guns. It reminds me a bit of gnomes but puts a kind of Redwall (The novels, https://en.wikipedia.org/wiki/Redwall) vibe to the whole thing. The other factor I think is that guns can be easily scaled for a larger hand, its not as if you are trying to make a polearm work for a Guinecean, who would not be able to take advantage of the reach provided by a longer weapon due to it having to be scaled down so as to be wield-able.
Putting that aside, a major discipline that granted use of a few limited gun powers would probably also cover this. I can imagine it would work well with certain classes. A tangential note at best, but I have played the table top RPG pathfinder and mixed the gunslinger class with other classes like bard, rogue and inquisitor with fun results. I even think it might somewhat fit with a class focused on fire, or even just provided to all medium humanoids.
On the lore side of things I think there is quite an effective case for why Guineceans would have either shared or traded gun technology. Here I am going to provide direct quotes from the lore page on the crowfall site.
From the Guinecean introduction The merchant families of Guinecea were the first to establish trade between worlds. Our artists, the inventors of sculpture and stagecraft. Our duelists, the finest masters to wield a blade. Our engineers, the only to unlock the secret of munitions.
Do you doubt my courage, friend? My sincerity? My loyalty? My prowess as a warrior? Stand back, then, my friend. Stand back, watch and learn
From the rest of the page
Guineceans are a diminutive, gregarious people known to be forthright and honorable. They excel at exploration and scholarly research and revel in meeting other cultures. A highly-civilized people, they favor diplomacy and free trade over conquest and aggression.
(Bolded emphasis is mine, italics is for the quote as a whole)
I think these quotes well illustrate that the Guinecean peoples, seeing the struggle of all races to survive would probably be honorable and either share the technology, or at least build guns that other races could use and sell them to the other races. The quotes point out that they are an upright and honorable race that would hardly pass up the opportunity to help out while making a little cash on the side. A friendly and outgoing and trade oriented species like the Guineceans would hardly sit on a technology like guns, which as I stated above can easily be scaled for a larger user, when there was opportunity to help and make trade and meet new peoples.
I want to thank you for reading this wall of text, I wont provide a tl;dr because I think it worth the few minutes. I apologize if I come off as rude, this being my first forum post here, I believe. If you would like to argue otherwise, I welcome your input and thoughts. A last note, It may be that I am somewhat behind in the latest lore information considering most of what I drew from was just on the main website and game development is a fluid thing.