Here's a little wish list item I've had for a while. I realize that this may potentially be covered by UVW unrap, I think this would make for a quick solution:
Description: Editable UVW "primatives" similar to and FFD, or even an FFD (or simple handles) that effects only the UVW coordinates.
How Used: For quick adjustments of a UVW "primative" modifier. A simple check box to turn on handles to pull around. An example would be the ability to turn a Planar type UVW modifier trapazoidal. More-or-less control points for a UVW.
Feature Affinity: Self explanatory...