Most countries went with the flow of international pressure, rather than banning as a sovereign decision. It came to a point in which any country that becomes sufficiently soft on hard drugs is labeled a "narco state", and that's widely considered reasonable grounds for a military invasion! What we're seeing today is the chilling effects of that.
That's the worst of both worlds. What will happen is a lot of people will become "addicts", get the drug (legally), then sell it to drug dealers to cash out. Criminals will keep their profits high, but they'll decrease their risk (because the government will be a safe and reliable supplier).
As another commenter mentioned, I'd imagine a lot of drug trade (maybe not in heroin, but definitely in cocaine) is not hardcore drug addicts, but occasional (or even regular) users who live (relatively) normal lives.
And it is less risky. I'd support a system that gives I'd more junkies of the junkies aren't destroying their health, aren't stealing, have jobs.
But of you're only allowing heroin use for dependent users in a clinic, you won't destroy the black market. There are still people developing new heroin addictions in Switzerland. And not only new users will use the black market to get heroin. Anyone who wants to use it in their own home, anyone who wants to keep their use secret will have no other choice.
http://health.spectator.co.uk/the-case-for-prescription-hero...