I think I'm right in saying that to gain full Affiliate Membership a Country must have to tick the correct boxes, including in this is a domestic league consisting of at least 4 teams, which is now in place.
Last year however there was only 2 teams playing rugby league and Canada were considered to have not been an observer nation for a long enough period of time.
I'm sure someone may be able to explain this a lot better than me but this is my understanding of the situation.
Anyway the plan is to get a good strong domestic league and regular internationals so Canada will be ready for the step up.