A couple suggestions for this tool:

1) Be abl e to see the dynamic slope line without first placing a line. I have to click somewhere in my file for it to place the line in the 3 D model before I am able to see the line at all. After this line is placed, the line can be seen dynamically

2) Be able to toggle t he HUD when using the analyze trace slope tool. Often the line is covered up by the HUD and it is difficult to see what's going on. I don't want to have to place the line to be able to see it. Often I just want to see where the water is flowing, I don't want to ha ve to manage a 3D model full of miscellaneous trace slope lines.