It might seem weird to some people that of all the various schools of RPG design of recent years, by far the most creative and (in recent years) the most acclaimed has been the OSR. Acclaimed enough that the designers of the latest edition of D&D wanted to consult with people involved in its cutting edge. After all, not only did the OSR start out as a kind of backward-gazing movement, which showed all the (lack of) promise of being pretty much an insular and reactionary concept movement, but it starts out with the apparent "limitations" of having a lot of boundaries you cannot cross and still be Old-School.
But that latter detail is exactly the secret of its success.
The OSR is like the TARDIS: bigger on the inside. There's infinite space inside the box.
You can have a creative process where you say "anything goes", and some unusual things might be produced due to that process. But just as likely, you'll get a bunch of stuff that doesn't turn out to be worth much. Likewise, if you create structure that isn't founded on what worked before, you are likely to create entire movements that are hopelessly flawed from the start (like the Forge's GNS theory).
The OSR is a box; it has a set of limits. To design an OSR game, you have to play within the rules of what fits old-school concepts. On the one hand, this obliges you to have as your foundation the most tried and true set of design concepts in the entire hobby. On the other hand, it challenges you to have to come up with something more creative than you might have if there were no design rules; creative in terms of producing something that is new and innovative and yet completely recognizable as fitting with the design principle.
We've already seen a lot of incredible books: spectacular rules sets, spectacular adventures and spectacular setting material. Almost all of it is fundamentally compatible with almost everything else in the movement. You can pick any rules set from the OSR, pick any setting book (even if its default is geared to a different rule set), and pick any adventure (even one from a rules-set different than the previous two books) and run them all together in your game. More than that, you can pick and choose stuff from five other books: a random table here, equipment there, a sub-mechanic from somewhere else, and use all of it.
And I'm fairly sure that we haven't seen nothing yet. In the last two years or so the ante has kept being raised by one publisher after another, and one designer after another, daring or inspiring each other to do more creative things.
By working within that bigger-on-the-inside box, we work with a set of principles that keep the whole movement connected, but we also have an incredibly vast space to do stuff different than anything we did before.
That, to me, is the real value of the OSR. That's what makes the OSR great, and what I hope more people will be looking at in the OSR. While I love what a lot of guys have done so far, and look forward to seeing what they'll make next, what I'm most interested in seeing is who else will come along and make something new that is part of the OSR and yet totally different to what I've done with it or the other designers have done with it up till now.
Currently Smoking: Dunhill Diplomat + C&D's Crowley's Best