Giving evidence to MSPs, Mike Baughan, who retires today (Friday) as chief executive of Learning and Teaching Scotland, and Keir Bloomer, its vice-chairman, also criticised the way the flexibility now being afforded schools is being narrowly interpreted.
Mr Bloomer, a member of the curriculum review group, said he believed it is discussing the right issues, but it would not follow the rubric of previous reforms in setting out curricular models.
"What I hope is that it will be about directions, not destinations," he said. "It will propose a sense of direction for the curriculum, perhaps indicating how we start out on the journey but not prescribing in detail what the destination should be."
Mr Bloomer, chief executive of Clackmannanshire Council, acknowledged that such an open-minded approach could be risky. "People might well say, 'is this the best you could do?' or 'where's the bit that tells me what to do on Monday morning?'"
He criticised the subject-based curriculum as "a mistake", but both he and Mr Baughan, vice-chairman of the review group, stopped short of arguing it should be abandoned completely.
Good teaching will make pupils want to learn almost irrespective of the subject, Mr Baughan suggested. School had been a "miserable experience" for many pupils and the drive to encourage lifelong learning would never succeed if that continued.
The curriculum had to encourage a sense of curiosity, develop enquiring minds, stimulate enjoyment of learning and create a sense of social responsibility.
Mr Bloomer commented: "We need to involve young people more in discussion about what they are going to learn and why. Only then will we engage them in trying to achieve it."
The new curriculum, he said, would have a place for traditional examinations in some areas but not in others. But he and Mr Baughan called for the across the board flexibility now being offered to schools not to be simply interpreted as "sitting exams earlier".
Mr Baughan cited the joint LTSHMI document on flexibility in the secondary curriculum which declared that "passive, unquestioning acceptance of national guidelines will not find favour in inspection".