It's a pretty easy subject to keep, and I think if you're doing well and enjoy it, that's more important than scaling. What else are you considering dropping?
Well I'm considering to drop either Physics, 4U maths. But what I'm concerning is that if legal studies doesn't scale well at all, then physics may be a better back up unit because I have 12 =D
It depends on the rest of the state who do Legal Studies. It varies from year to year. You're better off keeping it if you're doing well. There's no point in keeping a subject you're not doing well in, regardless of how well it scales.