In the posted TV show, it was found that the availability of marijuana (including for those not legally authorized to use it) skyrocketed with the opening of the dispensaries. Indeed, some people with (red, in CO) cards are dealers. Because of this (hopefully) minority of 'patients,' opposition sees the dispensaries fueling crime. In the 5th or 6th episode of the show, the voting comes to a close and all the dispensaries in Ft. Collins are forced to shut down.
I propose, simply, to make it more difficult to get a medical card. Patients should be screened by responsible doctors, found to have a legitimate condition, etc. Medical cards shouldn't be given to dealers. There'd be really no need to close down legitimate establishments if the proper steps were taken to ensure the wrong people didn't have cards.
Once at episode 8 or 9, we start to see Josh (dispensary owner) become interested in research and development of medicines derived from the cannabinoids in marijuana that are not THC. Taking the "high" out of medicating is one more step to being a fully legitimate industry. There is potentially a lot of money to be made here. Obviously, pharmaceutical companies stand to lose a lot-- A LOT, so I don't think we'll be seeing the development of cannabinoid medicines soon, other than straight weed and the usual. But it's a great idea.