Being able to add waterfalls and water above the already set level would add another layer of depth to level creation, this does not have to be extremely complicated, for instance the water could function as a square or rectangular object which you then can scale in size, make sure it has the same properties as the regular water so you can for instance swim in it, waterfalls could also work the same way as scalable objects, and working together could add a lot of level/map detail (a pond on top of a mountain creating a waterfall for instance).
Water boxes/brushes have already been discussed im sure when the team get onto a revamp of the water/fluid section that these things will be taken into consideration.
Being able to add waterfalls and water above the already set level would add another layer of depth to level creation, this does not have to be extremely complicated, for instance the water could function as a square or rectangular object which you then can scale in size, make sure it has the same properties as the regular water so you can for instance swim in it, waterfalls could also work the same way as scalable objects, and working together could add a lot of level/map detail (a pond on top of a mountain creating a waterfall for instance).