Contrary to popular belief, 90 percent of a barrister's work is paperwork, not standing up and arguing. For every one minute you're standing up and making the other side look like shit, there are 2 hours of paperwork, research and study required into relevant issues related to the case that has to be done beforehand. The actual number is a little different but the point is, most of the time you're not even going to be talking. It'll vary from case to case obviously.
I plan on trying medical science and then if I like it, i'll head on up to medicine come postgrad. If not? Well bugger, I've got 100 choices. Mainly psychology, editing, teaching, journalism...really, I'm not going to be in a course that I won't enjoy doing. If I don't like the course i'll move.
It doesn't matter what anyone thinks of the course or what you get for a ATAR or what subjects you did (you petty bastards bagging out the extension subjects should be ashamed of yourselves). You put in as much effort as you want and you get the corresponding number. Whether or not you thought the tradeoff of time - effort - fun was worth it is up to you.
In the end, the HSC only tests your ability to parrot shit. It isn't an indicator of your intelligence, as has been said 100000 times before. The only time you'll be talking about the HSC in uni is to bag it out.