I don't think it's morally superior/inferior whether one memorises, or does not memorise, essays. For some people, memorising works; personally, I can't do it as I prefer writing essays on the spot, and I think I'd find it difficult to mould an essay if I had memorised it so closely for so long.
But what I think is being missed in this discussion is the fact that the HSC fundamentally means different things to different people. For some, they NEED a high mark/ATAR/whatever to get into the course they want, and so, they might want to memorise essays if that 'works' for them. For me, I know my estimate is a fair bit higher what I need, so I'm taking yr12 and the HSC as a time where I can hopefully get as much out of the content as I can, and develop a passion in History, Sociology etc. And the thing is, none of these approaches is 'superior' to the other. Nor is one more 'successful'. I wrote all my essays on the spot and ranked 6th in my grade for Advanced, and a top-10 school.
This is about what works for people; engaging is such arguments about whether people are 'fuckwits' if they memorise fails to see this point.