IMHO it is no shock they are publishing photos Kate's taken. It is key to the Royal family that they are seen as approachable, as normal, this fits in with that. When I saw them I commented to my wife that they looked perfectly competant if a little middle of the road, in fact ideally suited for public consumption, they need to earn deference and this is one more way to do that.
I'm certain she'll have a decent camera, and any £500 aps-c camera can take photos of this quality, they can also easily afford top of the line DSLRs with every lens canon or nikon make.
Additionally I've noticed that US photos seem to be subtly different to UK ones, I can't put my finger on it but that's my impression... perhaps it's the light, ours is generally bluer, softer and produces less saturated colours... I have a few californian, north aftrican and italian pics and the light is quite different compared to Blighty.
30D, 18~55mm, 100mmf2.0, various Praktica, Atik 383L+ mono & filter wheel, 12" imaging telescope