Big and complicated? That's just crap. First of all there are now numerous jurisdictions, including several American states, already doing it and we can copy from their work. That's not complicated. 
Possession of less than a pound could be decriminalized tomorrow and should have been decriminalized a year ago. Easy. Growing fewer than 5 plants, same thing. Easy, should have been done already, could be done tomorrow, does NOT require a massive national infrastructure. 

What's complicated is figuring out how to legalize it while still maintaining the incredibly profitable virtual monopoly of the majors selling through health Canada. Legalization isn't big and complicated, but building a permanent profitable industry for those private parties sure is.