An idea for a feature request: in pattern along path (both LPE and extension) and the scatter-extension, add a cumulate checkbox and an exponential parameter to the spacing, normal and tangential offset.
The result should be that instead of having the pattern evenly spaced/offset along the path, spacing/offset would gradually increase (positive value) or decrease (negative value).
So the dialog would look like the following mockup:

Ideas/thoughts/comments?