I think houses should be limited to 2 per IP, with a 90 day warning. Honestly I don't understand why people need more than one house, I think this was a carry-over feature that was basically the default rule for most freeshards. But with the popularity of Outlands, it's pretty untenable. If we reduced the number of houses a player could own per IP and opened a new landmass, had more small/medium sized homes with very small courtyards/front yards/porches that were recallable, and allowed strongboxes/custom doors within large homes that would only allow a single account to access the chest/door would allow people to move into their friends homes. If we did all of that, I think the housing problem would feel less strenuous.
Also I really like the idea of being able to recall into inn rentals.
Late to the party, but expanding current major cities to include surrounding premade towns full of empty houses, shops, townhomes, apartments, ranches, etc has always been my idea of an awesome housing solution. Players could rent out the lots based on their needs - be it retail, storage, or everyday living. You could rent a corner upstairs apartment overlooking the central square or a blacksmith building down Trader's Alley. These lots would require weekly rent payments to continue living there, automatically deducted from your bank. Miss a payment and you have 48 hours to remove your items before they disappear and the lot becomes available for the next tenant.
It's a nice alternative to buying and placing a home. It provides the closest living quarters to major cities with new and interesting living situations, introduces a nice gold sink, and it can be integrated aesthitically into the existing map.