You have to admit that our prison population would be much more representative of the overall population if non-violen drug offenses were prosecuted differently. Mandatory sentencing disproportionately affects minorities particularly blacks. That is one of my biggest gripes with our system today.
Drugs should be legalized, but even if they were, there is too much of a culture of acceptance of crime in inner cities. Too much shit like this: Homeowner Shoots, Kills Teen Burglary Suspect
So, massive reforms in drug laws will probably reduce prison populations and crime, to an extent, but many people will move onto other illegal hustles...
As for becoming more representative of the overall population, I really doubt that.