I agree. The Union is great, but I still don't think it examines any negative aspects beyond legal implications. IIRC they don't look at the portion of users who will become dependent and ruin their lives getting high or who will drive insanely high.
I mention the driving as I think this is an important part of widespread marijuana legalization in North America.
Science or not, I think a lot of people can wrap their heads around legalization, but a big stumbling point is how much is too much to drive? Without an accurate (and reasonable test, ie something that doesn't out you for smoking 12 hours ago and somehow takes into account tolerance) roadside test. Although I'm pro legalization, I still can't believe people smoke and drive, sometimes at the same time.