Replay Gain seems quite useful, but what I'd like to see is a measure of how much dynamic variation there is in the track. Something that reflects how long and how far from the mean the volume ranges. That way, I could construct a smartlist of tracks more suitable for playing in a noisy environment, such as my car. This may not be an issue for pop music, but for classical it's a biggy. Bach keyboard sonatas are easy to listen to in the car, but most choral music from the last century or two has way too much dynamic variation. Assuming MC doesn't already do this somehow, does anyone know of 3rd-party software that does?
I did notice that MC comes up with a number called "Intensity", but I don't think it's what I'm after (can anyone explain it?). It appears to range from 1 to 5, but I notice in my Bach collection, an album of 2- & 3-part inventions for harpsichord gets a 5, while an album of partitas on piano gets a 1; I expect they're both low in dynamic variation.