It would be great to be able to invert pressure input from wacom tablets for brush parameters in Photoshop. The most basic implementation would be an "invert" checkbox next to each parameter. A more powerful idea would be to have customizable pressure input curves for each parameter. This could be done with the "contour editor" used to control various layer style falloff options.
In particular, I found that the pressure input for the Mixer brush's "mix" slider was the reverse of what I thought it should be, but the ability to customize the input curves for all parameters would create many new ways to use the brush tool. These curves could also be used to control exactly how much force on the pen is needed, allowing artists to work at a comfortable level of pressure and still enjoy the full range of input.
Take a look at this topic at Photoshop.com and help get this feature implemented!