Bleank

There is a brush I want to edit, but in it's controller parameters, there is no rotation or Size X Size Y I can add controllers to? Why do some brushes not have some parameters, and how do I get them for editing? I can't even change the brush size / shape in the brush settings, or rotation in the side bar. It's strange.

it's 100% normal you probably want to use the Crepe Brush.
This Brush has another "rendering" engine than the other ( for the moment their only 2 kind of Brush ).
Each Brush engine has their own kind of parameter. In the case of the Crepe a spline is drawn and that's why you can modify the Sale X and Scale Y parameter.
The Brush engine used by each brush will be more meaningful in future release