This means that, ideally, the design process comes before the coding process.
It can be very dispiriting for a designer to come into a project somewhere in the middle to find that major design decisions have been made and cannot be overturned. It is common, for instance, to find open-source UI that mimics the data structures of the code rather than the foibles of a human brain.
If a designer were to join an open source project they would be seen as "trying to change everything", "dumbing down" and "trying to take over". Which would, in a way, be true - and probably exactly what was needed.
I've often wondered if we designers could start open-source projects: start designing, publish & document our designs, release our work to the open-source community and wait to see if anyone bites.
I have seen this happen before and it was amazingly successful: Coverflow. Andrew Coulter Enright, a designer and artist, published a design for "how iTunes should work" on his website. Jonathan del Strother, a Mac developer, bit and published an implementation. Cover Flow was purchased by Apple Inc. in 2006.
I'd love to see something similar happen with a larger open-source app. Any designers out there want to join me in starting a site for exactly this kind of workflow?
http://en.wikipedia.org/wiki/Andrew_Coulter_Enright http://en.wikipedia.org/wiki/Cover_Flow