Hi,
Sorry for the late reply. Law in general (no matter which uni in Australia) can be quite a difficult degree. There are lots of readings you will have to do each class and it could become overwhelming if you don't stay organised and on top of your learning. If you are a well-organised person or you can drastically change your study habits so that you do become well-organised, that will definitely make studying law a bit easier.
The other factor to keep in mind is that studying law requires quite a lot of writing (analytical essays problem Q's, etc) so if you are a strong writer or enjoy writing, a law degree would definitely be more enjoyable.
It is very much a subjective choice, but students who tend to be interested in humanities subjects might find law a bit more familiar, but that's not to say you might not enjoy law if you're not great at writing. I suggest you try out law for a semester or two if you're interested, as you can always transfer later. Particularly because USyd has a compulsory combined law degree, you will only study one law subject in S1 and S2 of your first year, while studying 3 subjects from your other degree. If law doesn't work out, you can transfer to that other degree without having lost much in terms of time.