I don't know either, but philosophically I'm inclined toward more art, less science. To me, the one-size-fits-all approach is one of the shortcomings of modern music, not in any way moving the ball forward. When I hear new music I like, it hasn't been homogenized to death and has something unique / quirky / special about it. In the end there is no accounting for taste. The approach is at least as varied as ways to play the bass: Pick? Fingers? Thumb and Fingers? Slapping and Popping? Mellow? Round? Aggressive? Driving? Funky? Jazz? P-Bass? Rick? Hofner? Fretless? Electric? Acoustic? Upright? Bowed? ... to name a few. I'd hate to see someone run all those through the same blender.
My man! I guess it also varies on the genre, but this is how I'd mix my bass too!