I know many people are afraid of the complications of having to understand the nature of the world generation system system. Which is why only the Phoenix Terrain mod is still the only plug-in that existed to allow bukkit servers to create worlds according to new rules. However, I would like to make a suggestion for an alternative that is probably much easier to design and maintain whilst still allowing for server admins to have control over what their worlds contain. Put simply, I would like to see a mod or plug-in that swaps blocks in the world as new chunks are generated. And what is swapped can be controlled by the admins through an easy to use config file. For example. Lets say I want a server that is a vast desert. The mod config file would cause all dirt and grass to be swapped with sand and sandstone and all leaf, grass and plants and log blocks would be turned into air blocks to remove them. The same with all water so that there are no water sources. You could then have a survival server created with another plug-in to cause all food sources to be only available from mob drops or similar. Alternatively, the config file could specify depths at which blocks are swapped. So you could swap all water from 32 depth upwards with air and cause only water to exist deep under ground.