When I did GCSEs at my inner city state school, the second year after they were introduced, I was well taught by my teachers on a large variety of topics. Some of it had a coursework component, some of it was a case of revise all the topics and it is the luck of the draw what comes up on the day.
From what I gather, these days, teachers are forced to teach a much narrower syllabus, and they are teaching what the kids are going to be examined on. Therefore, there is a less scattergun approach, and a much greater chance of exam success.
However, the children end up less well educated. They do not have a broad base of knowledge. It is not fair on them. The whole thing is devalued.
But additionally the bar has been lowered a lot.
Both my parents and several of my friends work in Higher Education (where believe me, things are pretty shit these days, teaching standards have fallen as staff pursue their compulsory research and publishing) - they have no doubt that grades are vastly inflated over the last 20 years and in fact many universities have to run remedial courses to correct this.
Some kids doing English Lit GCSEs do not even read the whole text, just excerpts that they are going to be examined on.
I had the opportunity to tackle a GCSE biology paper from a couple of years ago (experiment with teacher friend) and I scored 92% - and I didn't even do GCSE biology! All my answers were remembered from science lessons years 7-9 (18 years ago) - if that doesn't indicate that they have got easier then I don't know what does.
It is not the kids fault - many of them do work hard and would rise to the challenge if the exams were tougher - it is the education system that is at fault here.