If it does become legal, I don't see it dropping immediately below Schedule II on the Controlled Substances Act. The most common indications would probably be appetite activation in cancer patients, and pain attenuation in Chronic Pain Syndrome and again, cancer patients. In other words, it is going to be strictly controlled, due to a combination of bad history (fabricated or not,) and the stigma that is still perceived in using it.
more on CPS
As for my desires for legality or not; I would like to see studies that can go through The Cochrane Review with the stuff. This panel reviews as many studies as possible to see if they are rigorously designed and if the data is presented and analyzed correctly correctly. This serves for the basis of evidence-based medicine ("The best studies that we have currently indicate...") versus "cookbook medicine" (e.g. giving every man between 15-80 a colonoscopy for colon cancer "because I said so." (there are certain criteria that state the proper ages (evidence-based medicine indicates a scope should happen at age 50 for most men, or age of a relative that had colon cancer minus 10 years. It grows that slow, and polyps removed at that time can actually be curative.))
If the studies can withstand the review, fine; let it come into the market. But as I said above, it will probably not drop below Schedule II for some time. However, if it is no longer a taboo (Schedule I) thing to do studies with, studies can be formed that can prove one way or the other to modern medicine to be good or bad for medical problems, which could move it on the Schedules.
Cochrane Collaboration main page
Cochrane Levels of Evidence
Trying to look at the subject as objectively (and hopefully realistically,) as possible. *shrug*