I don't think it's an issue so long as people are actually using the house in question. I use mine every day and I'm in a Free Company consisting of myself, my partner and the alt of a friend whose main character is on a North American server. My partner and I tried to find a FC to join and couldn't find one that clicked with us. I imagine many are in the same position.

A Free Company doesn't stop being a Free Company just because it is small and I don't think people should miss out on being able to get a house just because they happen to be in a small Free Company.