The exam reforms proposed by Fiona Hyslop, the Education and Lifelong Learning Secretary, spell the demise of early presentation for exams in S3, which has been pioneered by a small but growing band of secondary schools.
The consensus among the headteachers and education authority leaders who have been the trailblazers of flexibility over the curriculum and when to sit exams is that early presentation has helped to motivate lower ability pupils. They fear that, if this option is lost to them, there will be a loss of motivation among the pupils who are hardest to engage.
A presumption is already emerging that Ms Hyslop wants to see S1-3 modelled on the Australian "rich tasks" programme, where pupils are given a cross-curricular project assignment and assessed on a number of subjects.
Michael O'Neill, former director of education in North Lanarkshire, argues that when pupils are able to make their subject options after S1, they "attend better, behave better and achieve better".
He adds that Ms Hyslop's vision of a general S1-3 curriculum is not what the recent report on Scottish schools from the Organisation for Economic Co-operation and Development had in mind.
"It showed that the traditional, academic, liberal-type course is not appropriate for everyone," says Mr O'Neill. "But under this proposal, it appears that some alternative vocational courses won't start until S4.
"As a system, we do very well by the more able. The Scottish Government's proposal strikes me as doing very well for the more able but not so well for the less able," he adds.
Brian Miller, head of Dalziel High in Motherwell, South Lanarkshire, fears that the reforms will mean the loss of personalisation and choice for the pupils he has seen benefit from the chance to make subject options at the end of S1 and follow vocational routes in early secondary.
John Aitken, head of Keith Grammar in Moray, who has also pioneered early exam presentations in S3, believes that S1-3 is a natural unit.
His main concern about the new proposals is whether the new general exam replacing Standard grade and Intermediates will be a national externally-assessed exam. If, on the other hand, it is an internally assessed exam subject to external moderation, that moderation must be "robust", he argues.
"That is why doing our Standard grades in S3 allows us with total confidence to allow some pupils to go down the vocational route, because we know they have their baseline national qualification in their Standard grade," he says.
Another supporter of Standard grade is Neal McGowan, head of Larbert High near Falkirk. While he thinks some Standard grades need to be updated, he believes it is simplistic to argue for the abolition of Standard grade just because it is 24 years old.
He is concerned that it will be difficult to engage and motivate pupils throughout S1-3 if they do not have an exam focus.
"I am concerned that the issue of kids marking time between S1 and 2 will now be extended to S3," he says. "It is all very well for people in ivory towers, who are not delivering things in school, to say that if you get the curriculum right, that won't be a problem. But the people in schools who are trying to engage kids with flowery, thematic-based stuff, know it only takes you so far."
There was "intellectual confusion" besetting both A Curriculum for Excellence and the proposed qualification reforms, Mr McGowan suggests.
A number of the early presentation pioneers support the principle of giving pupils two clear years to sit their Highers. However, the idea that Higher candidates could by-pass the new S4 general assessment raises a number of issues. Where is the safety net? And will most schools, unwilling to take the risk with borderline candidates, not err on the side of caution and enter pupils for the new general exam in S4, followed by Highers in S5?