hmm i know that HSC timetable is structured more in favour of teacher's marking then it is in regards to the students.
So most likely the combining of SC and HSC is to assist with teacher's marking.
Its understandable however that SC results come out quicker, more multiple choice, they are all statewide compulsary exams, less aligning of marks and scaling, no UAC exporting of marks.
dont think things would change unfortunetly. but i am empathetic to the HSC students who have to finish WED due to SC exams, although they should see the positives too, more time to cram