I suppose Kate and William would have had an easier life if they weren't royal, especially him, born as they were into wealthy families. I wouldn't want to be on show all the time, and most of their official engagements will be deadly dull. And to be fair, I seem to remember she only took a month or so "off" after giving birth, whereas my DD has just had a full year mat leave.
Yes, "waste of good air" is vitriolic, the sort of phrase I'd use for a criminal, rather than someone just carrying out the role he happened to be born into.
Exciting times,ahead for you, gillybob! 