Do you mean when someone engages in a personal or property crime while on drugs? I assume under this balanced approach, possession, sale or manufacturing of "drugs" would not be a crime.
I do not think that committing a murder sober should be punshed less than while under the influence of drugs or alcohol. I feel the same about hate crime: is it more wrong to kill someone because of their race, or for the money? Is it more wrong to slay someone with a firearm or your bare hands? No.
I believe with any softening of our stance of drug prohibition should come a strengthening of penalties for all crimes. In my opinion, child rape should be a capital offence. Why is there such gnashing of teeth over what to do with sexual-offenders? If they are such a danger, don't let them out of prison. Likewise with murderers.