I think there are so many variables its often hard to pass judgement. One major issue for me is the maturity of learners both in terms of outlook and knowledge when modular exams are thrust upon them in the first term of year 10 (and for many year 9). I think the same pupils sitting a module in November of year 10 is not going to always do as well as that pupils in a linear in the June of year 11. Pros and cons but for me a 2 stage GCSE would be ideal. Pass year 10 and then onto year 11 exam in one form or another. I don't rate Gove though.