A random timer set for at least 2 days to 7 days and the house can go up for sale any time during this time is the best way to reduce flipping housing. I have had a house for most of the time since personal housing came out. My first house was a medium in Goblet and I gave it up(demolish didn't sell it) early this year as I was using it less and I was hoping to get a new house when SB came out. I gave a shout that the plot was open just to annoy a few that were selling their houses that day on the server. Even though it gave a bunch a chance at the house it would have been better to have had a random timer on it.
In the new SB housing I did get a house when many of my friends stayed up all night also, some got a house, most didn't. I did see a few of the plots back up for sale later for a crazy price. That should clearly be against the rules. You should not get gil back for auto demolish, you should only get gil back from SE for giving the plot up and letting a random clock pick the time when it can be bought again to prevent players that own land from flipping it or profiting since housing is a very limited resource currently. Maybe one exception to this, allow us to send a bid to a house that is already owned to an SE control market. SE can see our gil and its sources to track for RMT. The owner of the house gets a fixed amount if they accept the offer and SE could request a tax for using the system(gil sink) plus lock the land to you for 90 days. The idea of the tax is to make it unrealistic to make gil flipping a house while allowing the persons house you would like to get a small profit if they chose to sell it to you. As it is now, we have to go straight to the owner and ask if we want their plot and the can profit as much as they want to sell it to you. My idea while pricey, only eliminates flipping the house for profit. ie, house costs 20m, The owner gets 5m to 10m to give it you through the SE sales system(all bids in this system are blind so the owner does not know who wants the house). SE charges you 60m for the house plus say 5m that goes to the owner to give it up. Once you own this house there is no profitable way to sell it because of the tax. Just a side thought.
Part of what is insane as I was recently reading is that the Japanese have more servers than us. Why is that? About the same numbers play on JP data centers as NA data centers. Their servers run so much smoother. I was over on Yojimbo server for a while when SB released and the NA servers were a mess. Even the alts I have on the JP servers work better(runs much smoother and this is with a much higher ping than on my current server Behemoth). Why not add another data center for NA players for a better experience. While that does add more housing I doubt it comes close to the housing we need for NA data centers. Feels like the NA and EU subs are subsidizing the extra JP data center.
In my experience what we need is another data center and the same number of servers as the JP players have. Second, they need to take the current amount of housing on NA servers and double it. Last add another 2 to 3 slots to add friends on your house. I have always had friends on my houses since they don't have theirs or are looking to use a house while waiting for one to get hit with auto demolish. I find while location was nice, many of them liked the decorating part and the gardening features the most. I took a small corner of the house where I can craft and I let them do what they wanted with the rest of the house. This last idea is not the best as many want their own personal home to share with a close friend, RL husband/wife or bf/gf. Though this is a quick cheap fix in my mind, how hard would it be to change from 3 to 6 friends on a house? it doesn't make it an FC. The three friends on my new house often just like being in the ward chilling in the front yard plus they are working together to decorate the house, something I am not good at. I am glad to have them there and I know they love being able to use the house as all three friends missed buying a plot in the new housing. Though I understand many might say six friends is too much or most players would never let their friends do the things I let my friends do which is most likely true.
Last and least popular idea, bring the price back up(across all servers, every house on every NA, JP and EU DC all cost the same) and crack down on RMT. It makes housing something you work forward to get. I have spent many long hours crafting to make my gil. I lost time to do raid and some other content as I was often very busy crafting and had little other time. Gathering is profitable, so are map drops, clusters from hunts and some raid drops that can be sold. So there are more than enough ways to make gil.
These are just a few ideas hoping to help. I know not all of my ideas are good, I just tossed them out there.