Here are the basic assumptions, principles, and guidelines I'll be following to develop the new martial arts list for Street Fighter: The Storytelling Game. These are in no particular order, and probably aren't complete, but they're an indication of where my thinking lies right now.
Inspiration, not simulation: Many of these styles are inspired by real martial arts, but I won't be attempting to model real martial arts in any particularly rigorous way. I'm more interested in a fantastic version of a style that captures something unique about it than I am in detailed, real world accuracy. In the real world, glima, an Icelandic belt-wrestling folkstyle, has a number of restrictions on posture and movement. In the street fighter world, that form of glima exists as a highly ritualized version of the contest, but as used in the street fighter circuit it is a style that combines fierce throws with rune-based chi powers, the icy breath of the north wind, viking berserker rage, and techniques for immediately returning to a standing position if knocked prone.
Account for video game interpretations: That said, I'd like to be able to account for all the video game characters, and video game interpretations of the martial arts will heavily influence the style lists. In the street fighter universe, yoga is a martial art, and Dhalsim is its most famous practitioner. My first stop for representing some styles will be the street fighter video games, but other quality fighting games have a lot to contribute. To that end, I'll take inspiration from SNK games like the Fatal Fury, Art of Fighting, King of Fighters, and Samurai Showdown series. I'll also leave room for inspiration from Tekken and Virtua Fighter.
Look for patterns, and interpret them:This applies to the video game as well. There is a rough correspondence in the video game between Japanese martial arts and the use of hadouken style projectile attacks. It isn't a perfect fit, but it is a tendency. Of the kung fu stylists, only Chun Li has a real projectile attack. That's interesting, and I'll be building it into the style designs on some level. I'll also be looking for similar kinds of patters wherever I can find them.
Styles do not need to be balanced: Game balance won't be a primary issue when designing the styles. Players choose a martial art for their character based on a number of factors, only one of which is the effectiveness of its actual combat maneuvers. The aesthetics of the style are also an important influence. I won't be particularly worried about making sure that all styles have an equal number of maneuvers, for example. I will be trying to ensure that every style has some top-level special maneuvers. This way, if we're using our "multiple styles" rules, there will be some reason to top out in a style to get access to its highest level maneuvers.
Uniqueness, not effects-based design: There's been plenty of talk on blogs and forums about the value of glorious idiosyncrasies when it comes to powers, and I think this approach is the most true to the spirit of the original street fighter rpg. The alternative is a thoroughly effects-based design, which I've pushed the system toward in the past. It's time to pull back from that. An effects-based system can certainly be used to construct a wide variety of unique maneuvers, but they're all built from essentially the same set of core options. Street fighter maneuvers (and by extension, styles) certainly do have shared features, but I will be erring on the side of introducing uniqueness rather than systematicity when it comes to filling in the style lists.