Totally remove placard purchasing/transfers - 100% agree. The hours of clicking is ridiculous. I think when a house becomes available a 24hr timer should start. You could click the placard (as long as you have sufficient gil) and agree to buy. Anyone can do this within the 24 hr period. At the end of the 24 hrs, the house is randomly assigned to one of the players that agreed to purchase. This would solve the clicking all day problem.
Weekly lottery in each district - Not sure what this is?
Medium and Large restricted to FCs - I think larges should definitely be restricted to fc's only. Mediums and smalls should be accessible to both individuals and fc's. IMO
One per account - Yes, yes, and hell yes
Increase plot costs - Yes
Good ideas! Definitely something that needs to be brainstormed here on the forums and at Square.