How about actually researching it before we make up our minds?
Let's get the real data on addiction rates, effects on brain development and cancer risk and so on, how well it works against MS, how long it takes to eliminate it from the system, how badly any given level in the bloodstream affects driving ability and so on and so forth, then make rules about it, rather than just being offered "it's totally harmless man the government just wants to ban it because they don't want us to have any fun" and "it's evil evil evil and the gateway to other drugs and hell and if you touch it you're hippie scum who'll never pay back into the system what you owe the country for the privilege of living here which you don't deserve because all drug users are child-molesting rapists who want to destroy Our Great Nation!" The first one is actually quoting someone. The second is parody, but the capital letters near the end are quoting someone.
Of course, it's pretty much impossible to get that research done while it's illegal.
Personally, I think you need to look at means of delivery as well as the substance itself.
Given my very own chain of mineral-rich mid-Atlantic islands just north of the hurricane belt with lush environments and lots of money, I'd quite like to allow the stuff on one arc of islands but not allow smoking of anything anywhere. It'd take fifty years to get any really useful data, but it'd still be interesting.