Currently we are restricted to using a randomized noise map that is applied to each terrain textures layer with height values. I would like to see this replaced, or possibly just an alternate option that would allow using a terrain painting tool that treats each layer as a mask with the lower most layer always visible as the "Base layer".
In addition I would like to see parcel owners in regions with access to these tools without being an estate manager. This would allow parcel owners greater ability to terraform and texture paint on their parcel.
Each layer excluding the "Base layer" would be treated as a mask that can be painted onto the terrain via a terrain painting tool that paints in that layers mask. By default all layers excluding the "Base layer" would not be visible until using the terrain painting tool.
This tool would allow you to select which texture layer you would like to paint with. The region terrain textures would be categorized from top to bottom, with the top most texture taking priority when painting in its layers mask. This means the top most layer would paint over every other layer similar to how using masks in photoshop with layers works.