Hey Lonewolf!
My overall answer to this question is that you need to have case studies for each of the four topics. Whilst it appears that NESA may favour the other three topic over finance you never know when they will throw a curve ball so it's best to be prepared. Even if you don't get a finance essay question it is always good to have a few finance case studies up your sleeve for short answer questions to really maximise your marks there.
It is easy to say that if given two options for an essay - a finance question and any other topic - you would choose the other topic, but really you can't decide this until you see the exam because you never know what curve ball NESA will throw. You may not know how to answer either if you go in automatically eliminating any chance of a finance essay (which could also really screw you over if you get asked about finance in the report and you aren't prepared)
I know finance is the most dreaded of topics but avoiding it altogether will not do you any favours in the HSC, the goal is to be prepared as possible and so you should treat it like all other topics and gather case studies. It's really not that scary once you get into it so my recommendation is just to start.
Hope this helps