JD is always possible but the majority of JD students I meet regret not doing the LLB while they had the chance because they've found that they've been limited in what they wanted to do with just their single Business or Commerce degree and now have to tough full time work with full time law in order to get where they want to get. I went through a similar thing as you did last year but all JD students tell me not to drop it and just flesh it out while I can because it'll be beneficial in the long run.
The only JD students I meet that don't regret not doing an LLB are unemployed and can afford the time put into law school or mature aged students just wanting to learn more about it
Business Law is a watered down version of real law so it is quite naive
What you get in Business Law subjects is a gist of what the laws surrounding something like Contracts are but in application you won't be able to actually do anything with that knowledge. Most people I know who do it end up dropping it and taking up something more practical like finance/accounting to add more employable skills to their palate.
And if you think about it there's no real use of a Business Law major because you'll be outsourcing any legal work to law firms or your in house legal team (if your company is big enough) anyway, and the most you'll be able to do with that knowledge is gain an expectation as to what the lawyers will come back with.
A lot of people drop law after their first or second year. Foundies represent nothing close to proper law school so if you want, you can wait out the year and gain your opinion of whether you like law school after your first semester of real law subjects.
If it's investment banking you want to do, you'll need a law degree just to be on the same level as the other competitors. Working in a bank on its own is ridiculously difficult to get to, so you'll need to consider if you really think you'll be able to compete with everyone who hold a law degree and commerce degree applying for the same position with just your commerce degree. If you held a co-op at UNSW (worth applying for if you want to drop Law), you'll be able to make it easier. But a law degree will always be useful because of the skills and knowledge you will develop in the degree. Being at uni for another 2 years also isn't actually that bad. I know first hand how frustrating it is because you can't really do anything like preview programs or vaccies programs as early as other students but it also means that you have more time to maximise your experience and extra-curriculars and to get your name out to recruiters before you even apply. Being on something like the Business society at your uni can help with that incredibly, and having a law degree by your name is always going to be beneficial in your application.
It might also be relevant to know that PwC has gotten rid of their graduate programs, and it won't be long before the other Big 4s follow suit. This is just in the world of Accounting firms atm, which is no where the league working in a bank is. I have read that acceptance rates at banks are as low as 2-3% in literally thousands of applicants. Usually less than 20 people are accepted into graduate programs. Westpac had over 5000 applicants last year and picked 8 for internships/grad programs. This is all stats and knowledge you can find reading articles on Bloomberg or in the Financial Review and other finance publications.
IMO you should just stick it out, but I can understand that law school is retardedly intense and seemingly a waste of time if you don't engage with it at all, or if you don't even want to go into that field. But don't make the mistake of assuming you're the exception or on par with the exceptions you've heard of. Getting a job will involve so much more than just the degrees you hold. You're already in an advantageous position for what you want to achieve, so be conscious of that before you make the decision. Don't forget you might also be able to schedule your degree to be only doing commerce subjects for the first 2 or 3 years and delay your law subjects until later, giving you time to get the relevant experience you might need. I have a friend currently doing that and if he is able to get into the job he wants at an accounting firm or bank, he'll either keep law if the firm wants him to or drop it if they say it's not necessary.
Also a credit is a good mark for Law
Considering majority of students who don't fail pass, and that most law subjects have a <5% D rate and <2% HD rate a credit even if you're scraping it is good.