I am also quite excited to find openshot as a previous user of VideoStudio on windows. FYI, VideoStudio is now owned by Sony, and is a cut down version of their Vegas suite.
It provides a means for putting an audio "envelope" on an audio track. You can click "points" onto the envelope line, which can then be adjusted up to +5 dB, and down to 0 dB. A pan envelope for adjusting stereo balance can also be applied, but I have not used the latter personally.
It is also possible to apply fades by click and drag of the end line of a clip to create a quadrant at the beginning and end of each clip, and different curves can be applied to each fade (cosine/hyperbolic - I think). I'm not suggesting the latter be copied, but could be kept in mind as potential future enhancements. The same trick of dragging the keyframe into a quadrant can be used on video fades also.
Thanks anyway for a program with great potential.