My recollection is that Gove's original idea was to scrap the GCSE completely and replace it with a new 16+ qualification consisting of a single 3h exam for each subject. Maths represents a difficulty of course as the range of ability encountered at age 16 for all 700,000 children each year is huge. Maths and science subjects differentiate by topic, wheras Humanities subjects differentiate by response to a brief.
As a concrete example you can ask a group of 30 students to write two sides about the best learning experience they have ever had. Everyone can leave the room feeling they gave it their best shot. Some will be excellent and creative with a good range of vocabulary and demonstrating some self-knowledge and analytical ability. Others will produce a description description, possibly with limited vocabulary, possibly with deficient skills in punctuation, grammar and spelling.
Now ask the same group of 30 students to take a single Maths test. Some will finish in 5 minutes with full marks (it wasn't the right test for them) and some will take an hour and score close to zero (it wasn't accessible to them either).
'The Blob' (the education establishment in the UK, i.e. the people at the sharp end) managed to head this one off together with the QCA and the House of Commons' select committee on education lead by Graham Stuart - a conservative but with experience of work in education unlike Gove. The result was a re-vamped GCSE Maths in which the Foundation tier has some topics previously only found on the Higher tier such as trigonometry, surds, rules of indices with fractional indexes, simultaneous equations, quadratics: solving by formula, factorisation and substituting into to plot graph. Much of the more useful statistics has been removed (graphical presentation &c) and replaced with harder probability. Much more emphasis on technical algebra and difficult fractions/ratio questions.
This lot is working its way down the school system now. If they stick to it the result might be OK in 5 years but my guess is they will get stick for the atrocious pass rates for the next couple of years (or fiddle them somehow) and then fudge it.
[1] http://qualifications.pearson.com/en/qualifications/edexcel-...
[2] https://bettermaths.aqa.org.uk/2014/06/28/gcse-maths-topic-c...
[3] https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web...
