William & Kate is filmed as a real life fairy-tale romance. It's easy to watch and quite enjoyable, without requiring much thought on the part of the viewers.
The dramatic scenes are mere bumps, rather than the roller-coaster that they could have been. The deeper story wasn't entirely ignored, but it was skirted over rather than being the focus.
There is a comment on an Amazon review of this movie, which states that without the glamor of royalty, no-one would be interested in this story. It would remain as a fairly unremarkable telling of two young people falling in love.
I agree with that assessment as far as it goes. But I do think that William and Kate's situation is made more interesting, even in the usual royal setting, because of the history surrounding William's mother.
He has grown up knowing how dangerous the public eye can be. The hounding of the press certainly contributed to the death of Princess Diana. Now entering adulthood himself, he has to work out how to deal with that. Moreover, how does he protect his girlfriend? She is, after all, this generation's Diana.
These themes were touched upon in the movie, but very lightly. They emerged mostly in single conversations, though later scenes do show how Kate has to contend with being the new focus of the paparazzi.
Nevertheless, these emerge as mere troubles, rather than an ominous backdrop. They aren't explored too far; and they aren't used to convey any kind of warning or message.