There's already buprenorphine and methadone. But, using either means some degree of responsibility, punctuality, etc. So unless you mean freely distributing it with very little process, it wouldn't change much.
But there’s a whole space of harm-reduction before then, which is where things like the Swiss program to provide heroin in controlled circumstances can fit in.
An opioid without respiratory depresses on problems could fit into that sort of thing pretty well.