New Feature (Maybe), Not A New Idea
I also use Golden Cheetah to process my Garmin data. Golden Cheetah has a parameter called "Aerobic DeCoupling" that I like to use. It requires having a power meter (which I have). Basically, Golden Cheetah calculates your "Aerobic DeCoupling" as a percent. A value of zero percent is great, it means that your power output, relative to a given heart rate, is the same at the beginning of the ride compared to the end of the ride. A value of 30% basically says your power output is 30% lower at the end of the ride compared to the beginning of the ride, relative to given heart rate. Nothing new here, just something I like to look at and it would be nice to have it with my Strava data too.