Since this is a really, really long thread, I'm not sure how many of these ideas have already been brought up but here goes:
1. Redesign housing districts so that there is a central common area and instanced private and FC plots. The reasoning behind this is that whenever the devs want to add more housing to meet player demand, they always have to add new wards to existing districts which apparently requires a great deal of resources. With this kind of setup, only the common area would have to be instanced to meet demand which I believe would conserve resources taken up by adding all the additional wards. Another benefit would be that a mechanism could be implemented allowing players to upgrade and renovate their spaces and potentially setting up a way for players to actually build custom-designed houses. It may also be possible to set things up so that players can take their houses with them when performing a world transfer since the plot would be an instanced space much like the Island Sanctuary. If all that weren't enough, it would also be possible to do away with lotteries and auto-demolition if this type of system were implemented.
2. Make private plots shared among all a player's characters on a world. This just seems like a no-brainer because if players are going to be restricted to a single plot per world, then it might as well be shared among all their alternate characters.
3. I know this one is likely a repeat of others' requests, but increasing the furnishing limit would be nice; at least 10 or so for the outside and another 100 for the inside would be very helpful. From what I understand, many players have unused spaces in their plots because they reach the limit quickly trying to make everything look just the way they want.
4. There's still an issue that only "Tabletop" furnishings can be placed on loft pieces and other platform-type furnishings; most likely the best way to fix this might be to add a "Stackable" trait to furnishings typically placed on the floor or reclassify loft pieces and platforms as "placeable floors".
That's all I got for right now.