I can see lots of schools moving from GCSEs to IGCSEs in an attempt to avoid Gove's interfering policies.
Gove is going to crack down on GCSE "equivalent" qualifications. He has already removed all the "worth multiple GCSE" claims and stated they are all worth, at most, one GCSE.
Amongst those equivalent qualifications are, of course, the iGCSE.
If the GCSE changes, the equivalence will be broken. The iGCSE would have to reapply to be deemed equivalent to a GCSE. If the new-GCSE is more rigorous (or whatever) in the eyes of Ofqual then the iGCSE, as it stands, would by definition not be equivalent.
Any maintained or voluntary aided school which failed to do English, Maths and other core subjects with the Ofqual-accredited new-GCSE, or designated equivalents thereof, would instantly go into special measures, because they would instantly fail the floor standards. Ofsted wouldn't even need to wait for the results to come it: they could fail the school based on the exam officer's list of entries.
People appear all too willing to believe exam-board hype. Why is is taken as axiomatically true that cynical exam boards are dumbing down qualifications in order to win more business when the topic at hand is the GCSE, while those self-same boards are selfless guardians of intellectual purity and truth when it comes to setting things like iGCSEs? Why is CIE assumed to be an honest broker of the iGCSE, but a venal commercial concern when it comes to the GCSE?