Edith - I wouldnt change anything personally. Its others who want these changes. I am not sure though if they speak for a majority.
I am sure those schools set up with a specific change in school year could make their entry criterai to prioritise for different holidays. Of course the problem will arise when as you say parents who do not want these holidays are allocated such a school because others are over subscribed.
But one always has a choice. I am curently choosing home education for my DS for example I and I am a teacher and work in a school nonetheless).
If I sent my VS to school I would certainly want to choose one which suited my own holiday pattern - and its a traditional school pattern and one I like very much. Indeed being very honest, its one of the few remaining reasons for staying in the job now. Most of the other reasons I entered the job in the first place have been eroded to nothing or changed completely.
But other parents may see things differently and the new pattern may prove very popular.