In an interview with The TES Scotland this week, Mr Peacock did not go so far as to commit himself to abolishing Standard grade, but he now appears more sceptical about its future.
He held talks last week with Finland's Education Minister and senior officials as well as with unions, parent leaders and academics. The country is the top-performing nation as measured by the Programme for International Student Assessment (Pisa), which tests 15-year-olds from 32 countries in reading, maths and science.
Mr Peacock has in the past pledged not to "throw the baby out with the bath water" in discarding Standard grade just for the sake of it, and has praised "some very good Standard grade courses". But he now appears to be drawing a clear distinction between coursework and the exam.
While many schools in Scotland are turning to Intermediate exams in S3 and S4 as an alternative to Standard grade, the 20-year-old exam for 16-year-olds still has its stout defenders, as one of the debates at the annual conference of the Educational Institute of Scotland demonstrated.
Larry Flanagan, a leading EIS figure in Glasgow, said the "certification for all" basis of Standard grade could be put at risk. "There are still a lot of kids who leave school at 16 and one of the dangers in introducing Intermediate 1 and 2 at S4 is that they will fail these regimes because the assessment is different," Mr Flanagan said.
Question marks over the future of Standard grade are not new, but this is the first significant indication that Mr Peacock has joined the doubters.
Following his visit last year to New Zealand, which has a single upper secondary qualification, the minister cautiously described the position of Standard grade as "anomalous".
The Scottish Executive's official position is that schools should be free to innovate ahead of a review of Standard grade. It is already committed to "address the relationship between Standard grade and the new National Qualifications". The aim by 2007 is to reduce the amount of time spent on external exams, "including the option of sitting exams only when leaving school instead of sitting national exams every year from S4".
More generally, Mr Peacock was particularly struck by "the remarkable egalitarian spirit in Finland and the strong consensus on the importance of education, with a particularly firm view that the comprehensive approach was the right one. There is little debate about it." He also found "a very strong sense of ownership of the profession by teachers and highly developed collegiate working".
Mr Peacock said: "Teachers enjoy considerable respect, are regarded as acting highly professionally and are seen to be interested in driving up standards. We want to move in that direction and I believe we have made a start in the greater professional autonomy we want to give teachers, as well as more curricular flexibility for schools."
National guidance on Finland's curriculum, he noted, was "a slim volume".
One major difference with Scotland is the absence of a national schools inspectorate, although Mr Peacock has no plans to move in that direction. A high degree of peer review among teachers and a commitment to self-evaluation are Finland's preferred alternative.
Another significant difference is the absence of concentrated deprivation on the scale that exists in Scotland, which may account for Finland's strong showing in the Pisa results. Mr Peacock said he was now considering commissioning research to gauge the difference disadvantage makes to the performance of Scottish pupils.
In the light of controversies over the upheaval of school management structures following the teachers' agreement, Mr Peacock was interested to discover that Finnish schools operate a flat management structure, the norm being simply headteachers and teachers.
"It certainly hasn't held back their success," he said pointedly.
His main impression of the factors behind Finland's success was that "national consensus on education is the key".
Mr Peacock commented: "People agree that 'this is the system we want and we will invest in it to make it work more effectively'. This pays huge dividends for them."
Finland is one of the countries and regions of a similar size to Scotland which Mr Peacock wants to form part of a "benchmarking club" to compare how well schools here are performing.
Experts, however, are scornful. Brian Boyd of Strathclyde University said benchmarking attainment in this way was "a piece of froth", while Walter Humes of Aberdeen University called it "a worrying development".