i was in the same predicament with studies of religion.
i never actually wanted to do 2 units of it but my coordinator didnt quite let me drop it (but thats deserving of another thread) so this entire year ive been pretty unmotivated to do too much work in religion class.
Ive been getting pretty bad marks but im confident ill do well in all my other subjects so ive been spending most religion lessons this term working on other subjects (my teacher is a nice guy and i dont disturb the class). i still learn a few things about essay writing and such which can help in history and english and some of the topics that end up getting debated can be interesting.
in my opinion: if your assessment mark is probably going to be under band 4, and you dont believe youre going to do too good in the HSC, as long as your confident about your remaining subjects you may as well drop it.
remember a low rank doesnt necessarily mean a bad assessment mark, think about how the people with similar rankings and the class overall will do in the HSC.
also its a science subject so cramming is still very possible
