Terra-forming around the edge of water is kind of a pain in the ass. It lacks consistency.
For people interested in design/aesthetics, it would be nice if we could bring the terrain level down to be flush to the water level (or slightly above - or just a uniform height).
As it currently stands, there seems to be a predetermined height minimum/maximum associated with each tile connected to water, which can make leveling around edges of lakes - say for a dock - a pain and ugly.