i think quality plays the more important role in section 1 and 2. however i think in the essay/section 3, quality and quantity are equal.
i have to clarify though that quality doesn't only mean you have a sophisticated style of writing (and I doubt this is necessary in section 1, though it is important in the other sections). when i mean quality i mean concise answers that answer the question sufficiently corresponding to the amount of marks the question is worth, and go into detail. and by quantity i mean just how much you write, measurable via a word count, rather than number of points, or number of techniques (which I regard as quality)
edit: re: EbonyTW, that's the kind of thing I'm wondering about. Quantity in section 1 isn't necessarily proportionate to your other sections. First of all, note you usually have to refer to the 4 texts in the ~40 minutes allocated for it, which takes up a significant amount of time (i.e. you don't read it once, look at the question, then answer it without ever looking back at the text again). So markers aren't expecting that much. The other thing is that the 1-marker usually only requires 2, maybe 3 lines at most if your handwriting is about 5-7 words/HSC-sized line. 2-markers require 5, maybe 6 lines, 3-markers require about 9-10 lines. So there's one page, for 6 marks. The 4-marker would require about 14 lines, and the 5-marker needs bout 20 or a little bit more. In all, that totals to about 2 and a half pages? That will be sufficient, if your answers are concise, and contains the techniques and explanation for the question. Obviously most people can't be concise under exam pressure and tend to increase their quantity, hence I think anything more than 5 pages is overboard.
But yes, if you're writing a page, or even two pages of quality in section 1, that's not enough.