this one is a bit tricky, too, because again, you can sort of put components together to sort of do this... sort of. what's really needed is a component that, for the sake of demonstrating here, if you had a contour map, it would smooth all the contours down into gradual, on a gradient, slopes. it's not a blur, per se, and it's not a median or percentile. it's based on height of pixels and rather than give a hard line like a contour map, you'd simply smooth that down to the surrounding area based on radius control.
if something like this... or this, already exists, kindly let me know.
If wishes were horses... there'd be a whole lot of horse crap to clean up!
Craig