When you reclaim abandoned land, it would be nice if you could notify the nearby residents that the plot is available, to give them first dibs on expanding their land, rather than just putting it straight up for auction so that before you know it, that decent plot you were looking at suddenly gets some crappy club dumped on it, rather than giving you the opportunity to expand your land.
Why also not start all land at $1? After all, you've already recouped the cost of the land several times before it goes for auction, and you're just making unnecessary profit when you could benefit your users instead.
I'd add a clause that you cannot sell land for 7 days after you buy it, which would stop some of these dreadful land swoopers just grabbing a cheap plot, cutting it up and selling it on for a vast profit, screwing real players who are in the game for fun, rather than making money.
Those in it for profit will go somewhere else when they realise they can't make as much money as they were, it's your loyal players who are here month after month having fun and building "our world, our imagination" that you need to take care of more.
Lewis