It would be great to have a function to regenerate landscape using the inbuilt generator. Manually deleting a chunk ingame would almost do the same thing though so I don't know.

The issue is that the chunk is not always the region you want to regenerate. If you want to regenerate along defined lines, the chunk(s) touched by the to be restored area will have to backed up, regenerated form the inbuilt generator and then the area that you wanted to keep restored from the backup.

This function should work also for defined regions, and I think it is an absolutely needed function. The other option is only to restart the whole map, specially when new ores/blocks are introduced by notch. Only a regeneration can bring these into the game.

I will likely look into this next week. I've been interested in it myself.

Moved: http://redmine.sk89q.com/issues/71