I have no major criticism of the idents themselves, they are festive after all, and cheerier than last year's, but what's wrong with using an actual Christmas song as the soundtrack?
As the BBC have a bulk use PRS licence, it won't be because of licencing issues - although you'd think there would be a courtesy call made to that particular artiste to gain permission.
I suppose the feeling is that as you are being bombarded with old Christmas hits/festive tunes on the radio, advertising and as background musiac in every bloody high street chain store, having BBC One play them as part of the idents would be overload.
My user name might look like Hatton Cross, but it's pronounced Throatwobbler Mangrove.
dbl and Argybargy gave kudos