NESA published a document when they brought out the new syllabus, explaining the difference between the old & new syllabus (
https://educationstandards.nsw.edu....de-to-the-syllabus-in-biology.pdf?MOD=AJPERES). The old content was retained and a small amount of new content (on genetics and indigenous practices) was added. There’s also more emphasis on learning across the curriculum, rather than learning modules in isolation which is quite appropriate as everything in nature is linked and should be understood that way.
Past papers are still worthwhile to check you know the content very well, but I think the questions in more recent papers have been more broad or general - students probably think they are ‘easier’ in that they can probably write quite a bit for answers, but I suspect the examiners are now looking for answers that demonstrate a broad, deep and critical understanding of biology when they mark papers, so that’s what is needed to score very highly.