not sure why no one replied for so long but this is what i think:
at my school u have to do either SOR1 SOR2 or catholic and im doing SOR1 too and i know what u think, it really is just a load of crap you know but i think it IS worth hanging on to because if u work on it u can get a decent mark in it and its not that hard to get a band 6 in it (compared to other subjects)
as for scaling i know SOR2 scales just as well as economics (true story!) and although SOR1 isnt as good it would definitely be on par with subjects like legal, bio etc and also having that 1 unit up ur sleeve by doing 11 units (which we both do) it means whatever ur worst 2unit subject is (for me chem) only half of that mark will count eg
say ur worst mark is 70% (70/100) but ur SOR1 mark is 80% (40/50) then they take 35/50 from ur first mark and add it to ur SOR1 mark so ur worst mark goes from 70% to 75%!
i think u should do the SOR1 trial and then decide if it will count towards ur 10 best units, if u think it will then keep it, if u think its going to be ur worst mark then drop it, itll give u mroe time to study other subjects at the HSC