Things that need to be done for housing.

First off

Ward migrations. Low pop servers who don't need additional wards should be moved to higher populated ones that can actually use them. In other words, if there are empty plots they don't need more wards.

House removal system. If a house is owned by a player who hasn't logged in x amount of days and/or hasn't been subscribed for x amount of days the house is relinquished and put back up for market. If that person has been banned, the house goes up for sale.

Add a housing sales system. If someone wants to sell a house they can put it up for sale. It only goes up for sale the original price and that price degrades over a period of time. - To stop people from outing people for excessive prices and sometimes ripping people off. Possibly add a demolish fee if the house was bought in the past 30/60 days.

Free Company only wards.

#1 sounds amazing but the more popular plot locations can't simply be left alone and the unused ones given away to different servers, they'd need to redesign the map to make those plots still worth the money. Honestly, adding less wards (or none >_>) to the dead servers and more to the living servers would have been the smartest decision with their limited resources. Then again, I don't know crap about server infrastructure and whatever else relates to it, so it is what it is.
#2 is already sort of a thing but instead of logging in/subscription, you simply have to not enter the house for 45 days to lose it.

#3 should happen if only because it'd allow more people to enjoy housing, rather than anxiously wait for someone to never enter their house/spend double the price because of greedy people.

All very well said, though I know the activity bit was suspended, it is / may still be implemented again, though I remain doubtful.