I don't know if this would be possible in the future, but, could it be possible to allow special characters to be added to the chord names?
For example [E!] could be used to denote that the chord is palm muted etc. You wouldn't need to say what the special characters are used for, that could be up to the user. The allowing of additional characters such as ! * and ^ would be a great help.
At the moment, if I use any of these characters, the chords on the whole line are ignored.