WTFWG
As an author, I think the quoted W3C design principles are wrong, and putting implementors before authors is, counterintuitively, right.  According to the "worse is better" philosophy, "It is more important for the implementation to be simple than the interface"[1], and I believe that's correct. Complex implementations invite bugs and compatibility problems, which ultimately hurt implementors and authors alike.[1] http://www.jwz.org/doc/worse-is-better.html