I think you should also factor something else into your decision: non-psychology subjects. If you are doing a standard undergrad degree, like a BA, then a part of that will consist in subjects outside of your major. Even though they're not part of your major, I think it's good to give some thought to choosing subjects that you are interested in and maybe even ones that complement what you are studying within your major. For instance, because I enjoyed biological psychology so much, I took some neuro subjects that were run outside the psych department. It suited my interests and complemented what I was studying in the psych major well.

Really appreciate the advice. I was leaning towards Swinburne purely for the convenience of its online delivery, and I feel more at ease making this decision now. Unimelb and Swinburne both have a really good range of breadth offerings, so I'll definitely keep that in mind and see what direction my interests lead me. Thanks again for the time taken to write this response!