Broadly speaking, the W3C followed a specification-first approach. Figure out what should be implemented first and foremost. From this perspective, specs can be seen as blueprints for browsers to work from.
The WHATWG, by contrast, were implementation led. The way they saw it, there was no point specifying something if browsers weren’t going to implement it. Instead, specs are there to document existing behaviour in browsers.
I’m over-generalising somewhat in my descriptions there, but the point is that there was an ideological difference of opinion around what standards bodies should do.
This always reminded me of a similar ideological conflict when it comes to language usage.
Language prescriptivists attempt to define rules about what’s right or right or wrong in a language. Rules like “never end a sentence with a preposition.” Prescriptivists are generally fighting a losing battle and spend most of their time bemoaning the decline of their language because people aren’t following the rules.
Language descriptivists work the exact opposite way. They see their job as documenting existing language usage instead of defining it. Lexicographers—like Merriam-Webster or the Oxford English Dictionary—receive complaints from angry prescriptivists when dictionaries document usage like “literally” meaning “figuratively”.
Dictionaries are descriptive, not prescriptive.
I’ve seen the prescriptive/descriptive divide somewhere else too. I’ve seen it in the world of design systems.
Jordan Moore talks about intentional and emergent design systems:
There appears to be two competing approaches in designing design systems.
An intentional design system. The flavour and framework may vary, but the approach generally consists of: design system first → design/build solutions.
An emergent design system. This approach is much closer to the user needs end of the scale by beginning with creative solutions before deriving patterns and systems (i.e the system emerges from real, coded scenarios).
An intentional design system is prescriptive. An emergent design system is descriptive.
I think we can learn from the worlds of web standards and dictionaries here. A prescriptive approach might give you a beautiful design system, but if it doesn’t reflect the actual product, it’s fiction. A descriptive approach might give a design system with imperfections and annoying flaws, but at least it will be accurate.
I think it’s more important for a design system to be accurate than beautiful.
As Matthew Ström says, you should start with the design system you already have:
Instead of drawing a whole new set of components, start with the components you already have in production. Document them meticulously. Create a single source of truth for design, warts and all.