My sister was a functional alcoholic for 25 years. When she started heroine, everything changed, and she overdosed within 2.
She couldn't have been a functional alcoholic for 25 year if alcohol were an illegal substance.
There are plenty of people who have a normal life on methadone or heroin if it is provided to them.
As already stated, if you are an addict, getting the substance is the highest priority. Making it harder to get just makes them use more of their resources to get them.
It depends on the definition of "worse". If cell death over time, then maybe alcohol is worse. If it's how much a recreational/entertaining dose disturbs the workings of the mind, the operation/rational/ability to live a normal life, which is the purpose of the mind, then I would say heroin is worse.
I would assume the amount of dopamine a drug releases is directly related to its ability to disrupt someones life.
Making it harder for addicts to get heroin or a replacement will only increase the energy they will spend on getting it. This makes it nearly impossible to get to a better place in their life. It is mostly getting the drug that has a negative effect on holding down a job, not the drug itself.