New York City is a city, and France or Germany are nations. In the geopolitical sense, the two are very different. However, in terms of chapters the geopolitical boundaries are meaningless. Chapters are defined and measured by their levels of participation. We don't say that a nation must always be "better" then a city, we say that one wikimedian is equal to one wikimedian. A Wikimedian in WMNYC who pays dues and participates is equal to a Wikimedian in Wikimedia France who pays dues and participates. To say that one group of our volunteers should be discounted because they represent a smaller area is not a good thing.
So would you suggest that votes at chapter meetings, etc., be weighted by membership? That gets rather complicated when you consider that different chapters function in different ways (different membership fees, different responsibilities of members, different classes of membership, etc). If you have one vote per chapter then it becomes completely arbitrary.