I applaud your willingness to learn from accumulated facts - a quintessentially conservative trait, IMO. But legalizing use, although the liberty-respecting thing to do, will do nothing to reduce the value of black markets. Only legalizing sale (and keeping sales taxes non-extreme) will have that effect, as consumers turn away from the criminal market to the legal market.
I looked at the legal weed prices. $80 for a quarter ounce. I say no more.