Musical is not good enough for live sound. I want efficient 
Playing in front of thousands of people on huge PA systems requires a tight and clean bottom end, and the 6db/oct lowcut simply does not clear up the low end well enough for an ultra transparent mix, which you need for demanding venues and rooms. You should take a look at the Avid desks. The venue desk has an absolutely perfect lowcut for live sound! Preserving the fundamentals, getting rid of the messy stuff
A steep filter certainly messes with the phase, but that not necessarily a bad thing. Low cutting a kick og bass, you want that “hump” that phaseshift gives you. It’s part of what we are used to and like to hear from good filters.
