More wards in mist or some old, unused, mist mansions freeing up. The devs said they're adding some sort of system to take away houses from inactive players....however they never said if the system will take inactive players houses away immediately (3.1 drop), or if it'll be months and months and months of waiting for it to happen.

While I already have a private house that I'm happy with, my FC sold it's medium house and is looking to upgrade to a mansion. My FC has been waiting for quite some time now.