the diagonal line in the Curves tool

when working on the line in the curves tool (1), any change in one area result in massive changes in other areas (2). The pencil option is ugly and inaccurate (3). Could we have a new option, in which a diagonal line, divided into sections which will protect other areas of the histogram from changes in one zone will be displayed automatically (4)? 

1:

2:

3:

4:

Making these points yourself for every image is tedious and moves the line a bit as you determine the points. THIS IS TRUE FOR CAMERA RAW TOO!