The question about which drugs are most beneficial is kinda difficult, i just put benzos/amphetamines top as they actually have the most proven medical usage. But are we talking about simply recreational use? Because how would that really genuinely be beneficial other than just for fun (for most of them).
Also the question about most harmful, is that supposed to be most harmful in a strictly medical way, or harmful or society and/or the individual? I put heroin but medically it probably isn't.
And the classification system, are we supposed to give completely our own views on the classification or just try and make them in the correct order by the goverments standards? I just re-organized them in the classes in terms of harm but not sure that was the point.