The Queen is a bright woman, the wedding will be tiny compared with Charles and Diana's certainly, bearing in mind the Queen has previously tightened the belt of the Royal Family significantly and massacred the Civil List when questions have been raised about the cost of the monarchy.
On the subject of the Royals doing more for the country than most of the population, well for the most part they do. The Queen is the head of state, and carries out all the functions of one, she doesn't just go around the world on holidays all the time, she is actually working. Others on the civil list generally act as ambassadors and representatives of the nation, too, since the aforementioned cull they've been forced to by the Queen. Hard taskmaster, her.
Note I'm a long, long way from being a Monarchist, but I think people are quick to deride them when the alternative to our Constitutional Monarch would be a Political President (which most studies affirm would be more expensive). And nobody with any sense at all wants a political head of state.
EDIT: Spelling.