I am in two minds about going after fcs with very few or even one member.

Some people are not overly social. They might actually be happy in their tiny fc whether it's with just a handful of friends or on their own. I know it's common for many players to get a second house with a shell fc, but there are some out there who would have been in their tiny fc anyway even if housing wasn't a thing.

And well maybe in some cases the fc fell apart and the fc master does plan on recruiting and get it going again.

The point I'm making is, just because a fc is tiny or has only one member doesn't mean it's a player who made a shell fc to abuse the housing system. There isn't a system in place to check this, and I think it would be a bad move by SE to blindly clamp down on it. Instead SE should take away the incentive to make shell fcs.

A good start would be allowing all characters on the same server have access to the private house. I would even go as far as to say allow each character to have a private room, much like a fc room, so players can have little custom rooms for each of their characters. In essence a private home would be like a personal fc house for the player, just without the workshop.