That is a very interesting question, and we don't have a lot of evidence I can cite in research showing that people are attracted to one country as opposed to another because of more liberal family-class admission criteria, but the point was made earlier that, when family members are not able to join their loved ones in Canada, it is stressful. That tends to suggest it's a negative experience, and that experience is shared with people back home, so it would be surprising to me if it is not the case that the family-class rules that are in place in the immigration program have an impact on the desirability of coming to Canada and an impact on recruiting people to come for highly skilled jobs.
I certainly know that's the case in my own sector. In the universities, when we're trying to recruit from abroad, people look at the immigration rules that are in place. If they are going to come to Canada, they want to know what the rules are going to be relating to members of their family.
I can't cite research on this question, unfortunately.