green card in the US or in Canada? You are Canadian citizen, right?
After she lands in Canada and becomes permanent resident of Canada. Your wife has the right to move anywhere you want. Even if she moves out of Canada, it won't affect other people application (as in my opinion). It is absolutely up to you and your wife to decide where to live or where to go after she has her PR in Canada. It just takes longer for her to get citizenship status
In my opinion, if immigration didn't care where they live after immigrating, they wouldn't make them prove that they are intending to live in Canada. Of course it's their right to live whereever they want but if it's the intention of CIC that they allow this to make it easier for people who are moving to Canada with a foreign spouse and they find that people are using this when they are in fact not planning on moving to Canada, they will at some point reconsider if to allow this at all.
His wife will not be able to apply for citizenship unless she lives in Canada at some point for 3 years in a 4 year period. She will however not lose her PR because of residency requirements as long as she is living with him.