Mehitabel - I will happily disclose I can only really speak confidently about the impacts to English and English teaching.
I was Head of English and had been for three years in 2013 when I heard that Gove was changing the system we had worked with for years. The two changes made were firstly, that repeated entries for GCSE English would not count in terms of a school's results: many schools were entering Year 10 students, then re-entering those who did not get a C or above in November and then finally for those who still hadn't managed a C in the summer of Year 11.
This meant many sneaked through but the huge disadvantage was that it had an enormously detrimental effect on those who achieved Cs but should have been getting A*s, As and Bs.
The other change made was removing the speaking and listening (which had previously been 20% of a student's grade) from the specification, or more accurately, it no longer counted towards a student's results. As such, the layout of the AQA English Language and English papers stopped being 40% coursework, 20% S & L and 40% examination and became 60% examination, 40% coursework.
Now, the things I am in favour of are as follows: I am pleased coursework has been removed. The ridiculous situation, every year, in March, April and even May of English teachers running around looking harassed and careworn whilst smirking students wandered around quite happily, was crazy! There was always the risk of it getting lost (I am sure others will now inform me I must have worked in exceptionally disorganised schools but I have yet to have a year go by when someone's folder hasn't mysteriously vanished - always to turn up in the most unlikely place of course, but the stress this causes is horrific!) and then there's the task of getting it out of them in the first place: fine if you have reasonably well-motivated students but not if you don't. Plus, many schools had a tendency to spend a disproportionate amount of time on coursework and endless redrafts and revisits - technically not allowed but did happen - dull for students, unpleasant and stressful for the teacher, who also has to mark it if we are speaking of workload!
I am also in favour of the emphasis being on progress rather than on the 'C' or numerical equivalent. Too many bright students were not achieving their potential; too many students with lower attainment were being ignored because a c was not in their grasp. I feel this system is fairer and ultimately less stressful.
Of course, it isn't perfect and I have some criticism of it but it is far better, I feel, to our previous system and actually reduces workload for teachers overall (though at the moment we are of course all grappling with new texts and new systems.)