Many years ago I've read an article about an approach to user-interface design that mentioned changing perspective from “what could a regular user / any user use?” to “what would be the perfect interface for an advanced user?”. It was particularly insightful and claimed the change of perspective was fruitful. I think it could be an article about Plan9's interface. This week I'm searching for that article.
I'll need to search through:
I've just gone through the User Inyerface - a worst-practice experiment. It really is the worst UI, but it's not much worse than what we have to use nowadays…