Yes there has been lots of bike shedding. A lot of people, myself included, have lobbied that ! in CSS is already an abomination (because in normal programming it generally means 'not').
Currently the discussions/draft/etc don't match or agree on what the syntax or capabilities will be.
Our :-hitch-has is based on the original :has proposal and the existing implementation in jQuery as we feel that this is the best (and clearly the most powerful since it allows you to express more).