Legal has the potential to be an interesting course- personally, I don't really like it seeing as it's essentially just a lot of memorisation, but the content has the potential to be interesting. I've heard that you really dont need the subject to do Law at Uni, so if you're choosing it simply because of that, I've heard it's not a wise choice! (Coming from my teachers) And Yr11 content is pretty dry, Yr12 definitely gets much better with Human Rights etc.
My school studies World Order and Indigenous Peoples are our depth studies which I find super-interesting as they have a lot of social relevance.
In terms of why to study Legal above other subjects, it's not as conceptually challenging as other Humanities (especially the Histories) and you can breeze through the course relatively easily, although you definitely need to remain motivated and on top of notes, cases, and the media.