I wonder wouldn't it be more appropriate if you had to build over the land before you could claim it? To be more specific, you would have to build a large structure (maybe a wall, a tower, a mine ect...), and then from that point to as far as you can see is your land already claimed. Beyond your sight you cannot claim that land, until you build another suitable structure at that point. Borders will behave as normal when they get to close to each other.
So this is a new rule suggestion to replace the current easy claiming land rule. What do you think?
I would also have to point out, a proper structure would not include, for example: 1 block thick walls, or towers only 5 blocks high (depending on their radius). That way the structure is built of quality and represents proper dominance over the land.