I put together this little spreadsheet tool to optimize time spent flattening large or small chunks of land. You tell it how big of a rectangular section you want to flatten, and manually enter the terrain height for any number of terrain tiles in the area. It will tell you the optimal section to flatten with the least amount of work, and the height to flatten it to.
This could save you hours in the MMO release, and make it so you don't end up with random dirt piles that you don't know what to do with. If you've ever started terraforming and realized halfway through that you wasted hours of your life digging...this won't help with that. But it will help you optimize your time doing so
Here's a picture of it in action. In this example I want to find the best 6x6 section to flatten in a 12x22 section of land. The 6x6 section to flatten is in green, and I should flatten it to 3.8 height. I generated random numbers for the terrain heights for the example but they could just as easily be real terrain heights.
(full size: http://i.imgur.com/MtAP7EP.png)
I use the standard deviation of all possible rectangles of specified height/width in the given area, and pick the lowest one for the optimal plot to flatten. The height to flatten the plot to is just the average height of the tiles. If anyone can think of a better way than this let me know.
I made it in Open Office Calc (open source version of Excel), so it will work best there. It might work in Excel too, I have no idea. Give it a try and let me know if it works
Terrain Optimizer (choose download through your browser): https://mega.nz/#!FUgkSBwB!7QVcdDgIzfqdioaHPgdGXnJfO9tpsnOTeMflXKD_21Y
Open Office Calc if you need it: https://www.openoffice.org/product/calc.html