VCAA never looks for something “brilliant”, because a) that’s subjective and b) it’s impossible to quantify. High scoring essays doesn’t mean they uncover something revolutionary or take a perspective that no one or very few people have taken before. They have set criteria, and if the essay answers the question and is fluent then it will be given a very high mark.
If you want to check essays to see if they will get a high mark, always ask “does this answer the question?” and read it back to yourself (aloud is always best) and see if it makes sense.
I believe I saw a thread around here somewhere that had a direct comparison between a “bad” essay and a “good” essay, although I can’t remember where it is, or even if I’m creating a false memory. Chances are though, you can find easy comparisons and analyses on what makes a “good” essay.