Thanks, Fawful. (I've heard that you have fury)
I start off with Unity's terrain tools to create most of everything. For the water features, I take a screenshot of said terrain, where I've distinguished the path the rivers take, and use it as a reference in Blender, where I model the surface, following the form of the rivers.
For the cliffs, I've made a variety of cliff objects from a single rock, which I've rotated, scaled, warped, and such.


And then I just set them along the walls.
Trees and other vegetation also use the terrain tools.
So I've been working on modifying the combat controls to something that JWK5 suggested. The camera is still controlled by the mouse, but instead of two attack types spread over the left and right mouse buttons, attacks been streamlined to use just the left mouse button, and the right one's been made to target.
Attacking is rather simple: Holding down the button begins charging an attack. If the player releases the button before the charge finishes, then they do a normal attack. If it charges all the way, then it becomes a heavy attack.
That said, I should be able to get a little video out soon that shows all of this.