Should drug trafficker get death sentence?

Malaysian Yong Vui Kong, convicted of drug trafficking 47.27g of heroin and sentenced to the gallows, has hope. In Singapore, trafficking 15g or more of heroin will result in the death penalty. Their reasons include that he has become repentant in prison and that his death will not deter others from trafficking the drug.
In my opinion, he does not deserve the death sentence,even though he did surpass the amount of drug that warrants a death sentence by almost three times. Firstly, he did not harm anybody directly in any way. Some may argue that as the drug destroys a person's life, it is still the person's choice whether he or she wants to use the addictive drug. Hence, Yong cannot shoulder the blame alone.
Secondly, he is repentant over what he had done. I am sure that he is a first-time offender and did not know about the death sentence for trafficking over 15g of heroin. If he did, I am sure that he would not have done so. This is the other reason why I feel that he does not deserve the death sentence.
Instead, I think that he should be given a really long jail term, one of at least 10 years. I feel that first-offenders who traffic more than 15g of the drug should be given a long jail term, based on how much they traffic while second-time offenders should be the ones that go to the gallows.