Don't OSS project has professional designer? I mean like Apple-quality designers?
Have you ever tried contributing to a popular FOSS product? I have. Expect to be downvoted, yelled at, etc for suggesting change, especially change that's an emotional issue for geeks (implementing a ribbon-like interface, you know the one started by the 'evil' microsoft). Linus's childish attitude is pretty much the poster boy for this attitude. Namecalling is the norm. There are so many cultural and management issu…
A designer who can't code is dependent on other people donating their time so that the design can be realized. This puts the designer at an immediate disadvantage.