Things should be made as simple as possible, but no simpler. -- Albert Einstein
When doing my diploma in theoretical astrophysics in Tübingen I always tried to remember these words from maybe the most brilliant scientist of the last century. Staying to this principle really helped a lot when trying to understand many aspects of even the most complex and difficult.
I think that Einstein's principle fits very well for today's software development process including such complex efforts as a complete and feature rich desktop environment.