It may not work in rural areas but in towns that have 6 - 10 high schools I think schools could specialise and do it properly, not the way it is now. It would be better still if it was done with a first, middle and highschool so from 14 you could go to a school that really does specialise in music or languages etc.
Scrap league tables.
Obviously there would still need to be a strong general education for all students but instead of offering just 1 or 2 choices for GCSE a student who is talented at, say, art might be better taking GCSEs in History of Art and photography alongside Art rather than History and geography.
A musician might be better taking grade whatever in music rather than GCSE. And GCSEs (or other exams) should be taken when you are ready be that 14 or 19.
Students who have experiences/talents outside school should be able to take exams in subjects they have not been taught in school if they want, I'm thinking things like immigrant or bilingual children being allowed to sit language GCSEs.
I think we should not be so prescriptive about age, some children are ready for school earlier than others, and some would benefit from starting later.
I think basically put the child at the centre of the education system instead of politics being the centre. And basically have a look at what we are good at instead of constantly saying other countries are better.
Yes some countries are better but that doesn't mean that system would work here, some countries are better at teaching certain subjects and yes we should look at that, but not assume their way is better or would work with UK students.