I do int. studies at unsw, I can tell you that its specialised in whatever you choose to do and is far from broad depending on your major, though IR subjects are compulsory regardless of if you choose the IR major or not, learning a language for 2 years is also compulsory and so is a year exchange overseas. Im majoring in International business atm, but I'm combining it with law, if i don't get the transfer then ill also do eco as my other major and then do JD law. I chose unsw int. studies because from what people have told me, it's the most specialised int. studies degree in nsw, with compulsory exchange, IR subs and language making it attractive to employers i guess. at usyd i don't think the overseas exchange is compulsory unless I'm mistaken.
Personally I think that based on what you want to do, B. IntStud. majoring in international relations would be the way to go instead of just going with a standard BA majoring in IR. This would also give you more subs in the field of IR.
hope this helps