my physics teacher is a HSC marker and is an advocate for the new upcoming syllabus- simply because the long responses in the current HSC is basically how well a student can 'creatively' write
he said for longer responses especially for 6-7 markers, it is good to have a clear structure to how you write (step by step, dot point by dot point) so you can show to the marker you know the content front to back. However, most of the long responses for physics (ive noticed) do not actually require that much 'understanding' of physics itself, especially for questions that relate to society. my teacher said it is actually good to basically bs your way through. Not sure on the year, but he said he'd marked a question on how transformers had affected modern society, rather than talking about 'how' it works, most of the marks were dedicated to stuff like (less noise pollution, more luxurious items, more 'home' time) but it was also important to put disadvantages (more light-leads to more working hours, obsession with technology, obesity)
so all in all, depending on the type of long response- the more objective Qs you should have a step-by-step procedure in explaining it, while the more subjective is basically creative writing