You should make a build quality voting system. Have a profession (or make it the admins job or something) to go around and rate peoples lots out of 10, and then have it so the higher the rating, the more the owner is payed in land dividends or whatever. Just as a sort of way to encourage higher quality builds, and reward the players who spend their game time building with in game cash. Pretty much the same as irl, the more attractive your property is, the more it's value. I don't know how you'd make it less biased, but just thought i'd chuck it out there.