It would be great, when we could stretching and shrinking the selection in the envelope editor. Made a small gif animation.
+1
+1 
With proportional options would be cool also. I really like the way Cubase allows automation selection transformation - different areas of the selection that you click and drag on perform a certain type of transform.
And maybe something like this?
regarding OP’s request, if we had modulation options in the automation editor similar to the instrument editor, the envelope stretching would be like increasing/decreasing the ‘duration’ setting from a fader device.
Maybe next to mouse click dragging, it would be cool to have the modulation options for automation generation?