I played a bit with the terrain tools.
The toolbar looks nice. But there a problem with it.You need to much clicking to change basic settings, sometimes double clicking to open the slider.We talk about Size, Angle, Strength, Hardness, Noise. all this options have sliders you need to adjust many times. Now you need to click to many times between them to adjust settings.
It's more friendly and faster to but Size, Angle, Strength, Hardness, Noise in some properties window. SO all the settings are always open and you can change it with one click while you edit the terrain.
Example, something like this.
Improve the terrain tool UI interface. So you need less clicks and can access easy and quick settings.