This will more than likely never happen. It took about 24 hours to expand the map from 15,000x15,000 to its current size. Not to mention Andrew is a busy guy (at least from what I've heard) and this would take wayyyyy too long to accomplish. Many people would be unhappy, as this would cause the server to have a really long down time. Not to mention how would you classify something as abandoned. Obviously there are the half torn down structures, but there are still small homes and other things being used out in the wild. Also, not every builder would have the ability to store their items in a secured town. This would eliminate many potential long term users of this server simply because all of their items were destroyed. Not to mention, if you want to taste some fresh land, then go out to the newly generated area. I went to 1 location out there, and after 3 days, I am have spent 5+ hours going through 1 massive tunnel complex and gathered thousands of dollars in materials. I understand that all of the torn up ground and whatnot looks a little trashy, but you would have a better chance of trying to convince people to not destroy the build world, and to go to the mining world and destroy that instead.

 

This is the reason Andrew expanded the map. Now, there are more unexplored areas.

As for the concept of regenerating, you would lose everything. (Excluding donations)

 

One thing, just because someone disagrees with your suggestion it does not make them a "hater"