In addition to the idea "Elevation Profile Improvement", that lists a lot of suggestions for improving profile graphs, I would like to add the following idea:
I would like to see the profile graph update dynamically when the line used to generate the profile is moved.
To my knowledge, currently a line is drawn over an elevation surface such as a DEM and the profile is generated. If this line is then moved, the graph does not update to reflect the changed surface underlying the line. This causes the profile graph to be incorrect. This is a very easy error to introduce into your data because there is no way of knowing that the line has been moved and subsequently the graph is inaccurate.
This problem could be partially fixed by making the profile line unmoveable once drawn (except for being able to delete it), however I believe the dynamic graph is a much more efficient and user-friendly solution.