heather mack avoided the death penalty last week for murdering her mother and stuffing body in suitcase at bali hotel in august .
the 19-year-old got 10 years because she needs to take care of daughter .
andrew chan and myuran sukumaran were executed for attempting to smuggle drugs to australia .
the penalty came a decade after their convictions .
in that time , chan became a christian pastor and sukumaran an accomplished artist .
australian barrister says sentences should reflect the seriousness of the crime .