The plan will do nothing to address the inadmissibility of individuals to the U.S. who were convicted of marijuana possession prior to legalization.
Since Justin Trudeau became Prime Minister, I estimate that there have been over 56,000 "police reported incidents" of cannabis possession in Canada. Note that these are not cases where people are being arrested for a more serious crime, and the police also find a joint in their pocket. These are "federal statute incidents reported by police, by most serious offence." So in all these "incidents," cannabis possession was the most serious "crime" being committed.
In Nunavut and the North West Territories, about one per cent of the population gets arrested for a cannabis offence every year. That is an astoundingly high rate of arrests, especially when compared with cities like Vancouver, where such arrests are very rare. So, why continue to criminalize possession in some parts of the country and not others?
It is simply not a socially and economically healthy policy for society to say once a person is found guilty or pleads guilty, that we must, "throw the book at them." Also, we should also not lose sight of the benefit of a simple concept: mercy.