A few ideas of mine for the contour tool

1) allow a default number of steps...
At the moment this seems to be 4 by default and there does not seem to be a provision to change this. I would like it if this could be set when no contour was applied so that future applications of contour would have any preset number of steps desired (not just 4).

2)
http://wiki.inkscape.org/wiki/images/Ex_1.png
further to point "1" (and building on this) i think it would also be cool if the number of steps could be set to "0" in which case the contour would behave like an expand and contract tool. i.e the same as if you had contoured an object and then clicked the "inset path" command. But in this case it would happen automatically as the default would be set to 0 steps...
This would give this tool another aspect and reduce the number of steps required for users wishing to expand and contract objects.

3)
http://wiki.inkscape.org/wiki/images/Ex_2.png
Also the contour tool could have an "as copy" mode.
This would be have as thought the contour had been converted to shapes and then ungrouped (saving these two steps in cases where this was the intent from the outset)
Futher more as the image shows, when the number of steps is set to 0 the contour tool would function as an expand contract tool but this in tandem with the "make copy" option would mean the you could:

A) drag outwards and create an new shape behind the original or
B) drag inwards and create a new shape in front of the original.

4) Exclusion:
http://wiki.inkscape.org/wiki/images/Ex_3.png
This mode operates exactly like a normal expansion or contraction action (ie steps set to 0) except that the Expansion/Contraction action produces a "donut" effect.
(In the same way as if a new object had been created with the Expansion/Contraction and this was then combined with the source object with Exclude function.
This next image shows the same object with a reduction action applied with this mode.
http://wiki.inkscape.org/wiki/images/Ex_4.png

5) Radial Limit
This tool designed to be used with "exclused objects", allows the user to mask out any part of these objects radially.

The user simply grabs the large "clock like" handle that appears when this tool is selected and drags this around to mask out an area of the "donut" shape produced whe a "contour excluded object" is created.

This mask can be rotated around in a circle with-out effecting its "arc" thickness by using the little round handles midway down each "clock arm".

Picture (3) in the diagram above shows how the "Auto Smooth Ends" function works.

And picture (4)shows how an adjusted arc can be rotated to mask a different part of the shape.

N.B ITs worth noting here that even though this tool does behave like it is masking out the object below... it would actually be as if the masked section was a trimmed! This is VERY VERY VERY important as the real power of this tool lies in is ability to combine with the other tools here...

So that even though it would appear like masking the result would be like the trimmed section was an object in itself (outside of this tools editing mode).

This would allow feathering or expansions to be applied to this segment.
http://wiki.inkscape.org/wiki/images/Ex_7b.png