Actually, that's one of the guiding design principles for the WHATWG: ease of implementation for a developer is supposed to trump ease of implementation for a vendor every single time. How hard a specific piece of the spec is to implement in a browser is supposed to matter less than how hard it is for a developer to implement that part of the spec in code and on down the line.
Unfortunately, the WHATWG seems to do whatever the heck it wants to most of the time and having an idea collaborated on by the development community (the <picture> element) or working code (the <time> element from that whole fiasco a few months back) doesn't seem to amount to much.
I think that hidden gem has a couple chips in it.