My issue with the housing is the "inactive" houses - I don't believe they are healthy for the server long term, players feel more tied to a server once they own a piece of it, part of the land, and tend to be more invested when they do. When a person finally moves on from the game, and hangs on to that plot of land, refreshing it regularly with no real effort (just log in/out) - as opposed to upkeep, actually playing etc.. they are stopping future generations from finding a piece of Avadon to draw them in. I have zero issues with the housing economy itself, it's tied to inflation - people can make far more gold selling items or resources now than when the server first launched - so it stands to reason housing should be more expensive. But every dead plot out there, is a hole in the server that doesn't help generate more activity.
Inactive houses are from people moving on, and from VPN's holding houses for a better housing deal, though the latter I don't believe is a major issue compared to the people who burnt out getting their home settled, then got bored and started playing other games.
I don't believe in 1 house per account group - working out upgrades becomes extremely hard then - though with a settled server, it's pretty hard to find two houses side by side to upgrade - with the exception of finding/fighting for IDOC's.
I do believe in upkeep for houses - the theory being to keep an estate in top notch order, you need to sink some time & resources into it. Repair your roof, your walls etc.. It shouldn't be overly heavy - and it should scale based on the size of the house. The reason it should scale on the size of your house, because 1 30x30 house takes up 8 - 8x8 plots, so for someone owning the largest plot, that's 7 less people who can own their piece of Avadon. Upkeep will push houses into IDOC state faster once people move on - and get that land back to multiple people.
I also believe in taxing players who have multiple houses on their account group - it should scale based on the number of houses you have - because again your over indulging and stopping another player from owning a house.
I don't begrudge anyone owning multiple houses, but if 1 person wants to own 3 - 30x30 homes (not sure anyone does), that's 24 people who aren't able to squeeze an 8x8 on the map.. They should have to continuously pay for it.