I've come up with a JS plugin that lets you use your MIDI controller device to control volume, pan and mute for audio tracks. This means you can e.g. select a volume/expression pedal to control the track's volume, select a knob to control pannning, and perhaps the sustain pedal to mute the track. Of course you can record the MIDI data (on a seperate track), and then route it back to the audio track, wich essentially gives you MIDI-controlled track automation.
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You can use any regular CC, but you can also select pitch bend, or even note on velocity, or channel aftertouch. You can reverse the controller's behaviour, so e.g. the track's volume actually lowers when you turn up the modulation wheel.
In all honesty I'm not really sure whether I or anyone else would really need this plugin, or even what you can accomplish with it that you can't already do otherwise. But hey, at least now I know something about JS.