This is an answer to a question I get a lot, and I’ve answered a lot… and saying the same thing over and over is inefficient. So from now on, when I get the question, I’ll point the questioner here.
One of the secrets of the success of Basic Fantasy RPG is the fact that I had a clear vision of what the game needed to be. Four classes, four races, brief equipment list, manageable spell list, enough monsters to keep you busy without getting too weird, and so on. I had what I called a “coverage target,” that is, a list of things that the game had to have. I made a point of adding very little that was not on that list.
The rule I used was simple. Many people would send me email messages that said “Your game is really good, but it would be great if it had X in it” where X might be sorcerers or half-dragons or whatever. Very few people repeated the same request; when I saw a request being repeated, that was an indication to me of something I should consider adding. Consider carefully, mind you… very few things got added that way. It’s why we have (brief) wrestling rules, for example, rather than none at all as was common in the 1981 era that BFRPG seeks to emulate.
Any X that was requested by just one guy? No, not getting in, sorry. Even when several people asked, I was really careful.
One thing in particular I am always careful of… new classes. It is so hard to create a new class that is not objectively better or worse overall than the core class it is closest to. Balance is hard, people, especially in a game that embraces the “linear fighter, quadratic wizard” situation (look it up, it’s interesting reading).
The Basic Fantasy RPG Core Rules will probably never include more than the four classes and four races you find in the current edition. Keeping the game compact, and providing those “cool” bits as supplements, helps to keep the feel and style of the game consistent and familiar.