sorry, the question is; can you edit those graphs?
truthfully i'm trying to figure out why solar winds wouldn't let you use the radial odometers and make the display a little more customizable. by that i mean, instead of just checking off what you want to appear allow you to change it from a bar chart to a radial, or just %'s, etc etc.
You should be able to remove the trend line by editing the graph and turning it off in most cases.
Aside from that there is not much you can do to edit the graph beyond what you have already mentioned. The SolarWinds team is working on adding more customization capabilities to the graphs as you will find if you search the forums on the topic but no ETA on when that will be available.