I have no idea what the exciter does, but I love how it sounds. However, there’s one thing that bugs me: it raises the signal’s level, which makes it hard to do an accurate A/B comparison of the processed and unprocessed sound, since merely raising a song’s volume tends to make it sound better. Because of this, it’s hard to tell how exactly the exciter affects the sound.
This could be easily solved by adding an output level slider, so that you can adjust the processed signal to be equally loud as the the dry signal.
Yes, having a meta-bypass button for the whole chain would be good. You could get around this with use of send tracks, but it’s still more than a few clicks to get an A-B happening. Do it quick!