Do I encourage repeating? No.
Your internal marks get moderated and 50% if it is relatively bad, then it will drag you down. However, this is no time to give up. Just because your ranks may be "mediocre" or below your own expectations, it doesn't mean you shouldn't try for the externals which moderate the internal and provide you with 50% of your total mark (i.e. like doing ALL school assessments all over again including assessment half yearlies and trial exams).
With that said, I will say that repeating is not always detrimental. Repeating is to only occur if you had uncontrollable external issues that hindered your ability to do well (family problems, unexpected deaths, tragedies etc...). I know someone who couldn't study all year because of the death of an immediate family member (he was barely in school), he ended up with a 65-70 ATAR, which was 96 the following year. It wasn't because he was a natural procrastinator, he was just barely at school and didn't know what's going on.
If you're going to repeat for the sake of repeating and you had a smooth emotional and physical year, don't expect a big improvement in your marks. I say this with conviction because you're not going to study next year if you procrastinated all of this year, no matter how much you tell yourself that. Repeating the HSC can also come with a sense of complacency, "I know what I'm doing, I did it last year" which would obviously impact on further results.
