Synthetic THC is a Schedule III drug (like codeine), and readily available as a prescription. I'm always amused that fans of medical marijuana never consider using that instead.
As I see it, the only real harmful (in terms of health--I'm not sure I like what it's done to some people I know who have abused it) component of marijuana is the tar. It's certainly bad (there's significantly more tar deposited per joint than per cigarette, somewhat offsetting the reduced use), but it's not an addictive substance and certainly doesn't belong as a Schedule I drug. I would still keep it as a Schedule II (equivalent to morphine or adderall, for example), because it simply adds toxins over ingestion of synthetic THC.
Problem is, products like Marinol have nasty side-effects for almost everyone. It produces a far different effect for most individuals, when compared to the effects of the marijuana plant - especially to a quality cannabis strain.
Synthetic THC, when prescribed as a regular dosage of the chemical THC and nothing else, a pure product, is quite undesirable. When every marijuana strain -- complete with a specific ratio between THC and a host of other cannabinoids -- produces a high specific to that particular strain, it readily shows that complete package of total cannabinoid content is required. Each cannabinoid has a specificity to a certain type of neurotransmitter receptor, though will bind to both types of the cannabinoid receptor (CB1 and CB2 are neurotransmitter receptors to which all cannabinoids will bind, which also play host to a minute and somewhat uncommonly-produced endogenous chemicals that bind at those sites). Thus, each cannabinoid produces a specific overall feeling in the body, and it is the combination of multiple cannabinoids, at specific ratios, that produce a total overall feeling as each individual chemical binds differently, producing a total specific ratio of specificity of action at CB1 and CB2 receptors.
Thus, the best medical usage of marijuana, is for the "prescription", in the form of a recommendation, for specific strains available at the dispensary. That dispensary could be a marijuana-specific "store", or a true pharmacy (and they would need to stock multiple strains for this to be an option).
The best medical recommendation of consumption, would either be in vaporizer-delivered form or used in baked goods. Specific dosage is important, as the guideline/preferred medicinal value approach would be more appropriate, in contrast to getting stone. Of course, there would be nothing wrong with that on occasion, it should be compared to alcohol; you can have a beer or two (or some wine) with dinner, or you can drink more to get a good buzz, or even get drunk. Smoke one small pinch, and you'd probably get all the positive effects and none of the true high.
That serving size would also be most appropriate (as a suggestion or in metered-form) for commercial sales too. Additionally, companies wouldn't be stopped for making stronger or larger servings if sold in some serving-metered form. You can purchase alcohol in various serving sizes and in the measured alcohol by volume (ABV).
