If the overall objective, as outlined in the Official Languages Act, is to increase the demographic weight of francophones, we'd have no business choosing the communities that deserve an increase in demographic weight.
I understand that successful integration often depends on institutional completeness. However, if the problem in certain communities is a shortage of French-language institutions and services for the purpose of taking in and integrating newcomers, the first step is to solve that problem and to ensure there's a range of appropriate services with which to welcome and integrate them. That way, everyone can benefit from the collective efforts made to increase the demographic weight of francophones in Canada.