"These rules are as complete as possible within the limitations imposed by the space of three booklets. That is, they cover the major aspects of fantasy campaigns but still remain flexible. As with any other set of miniatures rules they are guidelines to follow in designing your own fantastic-medieval campaign. They provide the framework around which you will build a game of simplicity or tremendous complexity your time and imagination are about the only limiting factors."
In that spirit many of us pioneering Gamesmasters in the old days, before AD&D came out, created our own worlds, and our own rules systems. In fact in my town we had a fledgling Gamesmaster's Society and the entry criteria was "Anything but Gygax". We could use the three books as a basis, but every GM was expected to come up with their own version, fixing what we all considered to be fundamental design flaws in the original system. I did likewise, and within a month or two had worked out what I felt was a coherent, and easy to manage, flexible, and elegant solution to what I thought was the most fundamental design flaw of all in original D&D. The flaw was a function, I felt, of the TSR business model. I'll get back to that in a minute.
We had another reason for wanting to create our own rules systems. Early on GMs noticed that some Players had a tendency to want to rules lawyer the games, and second guess the GMs. So when a monster was sighted, the Rules Lawyer in the group would know all the stats of the thing, and have a good technical idea of how to maximize the party's chances of beating it. I'm not saying that this is a bad thing. But we GMs didn't care for it. We felt it kind of ran against where we wanted to go with the game. Which was toward story, not towards mechanics. We wanted the Players to focus on their Characters personalities, motives, and relationships, not their stats. A lot of people later on said that D&D was not designed for story, it was designed for Gaming. Well, I somewhat beg to differ on that. It was the first attempt towards what I will refer to as Story-Gaming. Before that the closest thing we had was Chainmail, which was a medieval military war game that used miniatures, and had very specific combat rules, and was indeed Gameist in nature. But D&D was a first shot at a more Story oriented game. It definitely is Gamist in that it had rules based loosely off of Chainmail, but it's concept was to merge game and story. At least that's how we all took it in those days. As such I would say that D&D was by design intent a Story-Game based on was Tolkien's 'Lord of the Rings'.
To return to my earlier point, the fundamental design flaw was the TSR business model. It ran against the grain of the Story-Game orientation of the original intent. The business model, of course, was to sell rules books. And to justify those sales the rules, I knew intuitively, would have to become more complex, and continuously change. This would, of course, cause us GMs to have to alter our Worlds as the rules systems changed. Magic? Totally changed. But if I had a world where famous Characters had used certain mystic powers to defeat an ancient threat, but those mystic powers were no longer in Rules Version 8.3... what would I do? I'd freak out, that's what. I wanted from the beginning a continuous long term campaign that wouldn't be vulnerable to the vagaries, flaws and alterations that would inevitably come down from TSR over the years. I'm sure that other GMs who I knew felt the same way at the time.
And so what we wanted was a simple, flexible rules system that would allow us to play out RPG Stories. We didn't want it to get in the way. We didn't want it to take over and become the primary focus. In fact, to avoid that effect we not only created our own rules, but we often obscured them away from the players. For many years I hid my rules from my Players. I hid their Character's stats from them, too. Instead of giving them a number for their Character's Strength, I would simply say, "He's stronger than average", "She's wiser than the hoot owl", "He's a clumsy oaf, but has the gift of gab", and so on. Guess what? The players absolutely didn't mind. I explained that I wanted the game to focus on story, and they were cool with that.
It wasn't for many years that I finally let my Players in on the rules. I did so because my interests evolved. I wanted to work on certain aspects of the rules system to iron them out, and balance them. To do that I wanted Player feedback. I explained, "I'm going to share the rules with you guys, and I would like to get your feedback on them in relation to combat tactics and game balance." They were totally cool with that, too. And so for the remainder of my GMing time I've been ironing out, simplifying and balancing them, with my Players help. It's been great. I know use a 1d6 system with one central General Resolution Matrix. Actually, the GRM I came up with back in 1978, but the 1d6 system was something I worked out between 2006 and 2013. (Don't rush me, I'm a slow poke).
After AD&D the industry took the expected turn for the worse in terms of rules complexity and what I think could fairly be called Anti-Modularity. Every system that came out was more complicated than the last, while purporting to fix the flaws of the previous system. Instead of tweaking towards simplicity the designers chose to revamp towards complexity. That's ok. There's a lot of folks who adore one or more of those systems, and don't mind the periodic World-overhaul involved with changing the systems. For me, though, and GMs of my ilk, it just didn't quite cut it. I guess it's because we were there in the beginning, saw the original rules and a launching point for our own systems, and went at it with a gusto. I've seen a myriad of wonderful variations on original D&D. Many of them were enormously creative adaptations. I've even co-opted a few of the ideas I found along the way. You'll find, for example, a certain resemblance between the numerics of my magic system and that of David Kahn's Telthanar. ;) Overall, I'm pro-Homebrew. While I'm not anti-other-systems, I have a definite preference for the local variety of creativity that comes with designing your own RPG rules system.
The upshot is that I'm interested in what other Homebrew style GMs have done over the past 30 years. If you've created and are running a homebrew system, drop a line. I'd love to hear about it!