It would be very nice to have the brush object have its own color gradient that can be applied in a 360 orientation.
This would allow you to set shadows/opacity/saturation based upon a controller for direction for example.
For example: set the left side of an object to be darker than the rest when drawing down, bottom darker when drawing right, right darker when drawing up, top darker when drawing left.
If I am making myself clear, right now when you draw with a brush, the changes are applied to the objects as you draw, whereas this is to make a difference in each object, that could then stay the same (or vary) as you make your stroke.
In other words, in the dots default brush, rather than having a black dot, followed by a pink dot followed by a red dot, the dot itself could be black on the left, pink in the center, and red on the right with opacity and saturation also individually set. This would probably necessitate a gradient bar within the brush gradient bar, but would give tremendous control over the brushes effects.
Hopefully that explains the wish successfully.