My career is what you would describe as 'PR for high profile people'
More business personalities than celebs, but broadly, I get hired to rehabilitate troubled reputations as well as improve and cement established one. I am going to go out of a limb here and I say I know a bit about how their PR strategy will have been put together, and what their priorities are.
In brief, there are always those media outlets who will be a 'lost cause'. You can have a good relationship with the journo on a personal level but if their editorial policy is to dislike a particular person, then you can't do much about it, and don't waste too much time trying to win them over. In the Cambridge's case, this is the Daily Mail website.
This is most likely not because the individual journos dislike them, but because the frothy readership always dislikes them, and the articles are clickbait.
There will also be the higher-value outlets, which are more critical for converting or cementing opinion.
I would wager that most of these are non-UK publications. The US and Asia will be strategically more important, because the royal family have strategic significance for international trade.
And they aren't fussed about royalty acting like middle classes, or aping the behaviour of their parents. They value the quintessential British-Ness that the Cambridges are playing up to with their staged photos.
There is virtually zero debate on the monarchy or civil list in the UK, and never has been. So we aren't the intended audience for the PR strategy. They'll be here regardless of what the Daily Mail- reading oiks think of Kate's hemlines.
The strategy is focused on the bigger fish, globally. So no, it doesn't need a rethink. It seems to be doing ok for now...