Magfan, You made this comment: "If I had the $$, time and inclination, I'd work on NOT running my panels full range. I suspect there are additional benefits in that direction, but also a whole new learning curve."
For my tastes, I found taking some of the lowest-frequency bass load off the main panels made at least as big an improvement as adding more and lower-frequency bass did. Articulation of subtle nuances (and some not so subtle) improved dramatically. My main complaint with add-on subwoofers is most just add bass and do not give the main speakers some relief where they need it the most. And you are right--it is a new ball game.
For my tastes, I found taking some of the lowest-frequency bass load off the main panels made at least as big an improvement as adding more and lower-frequency bass did. Articulation of subtle nuances (and some not so subtle) improved dramatically. My main complaint with add-on subwoofers is most just add bass and do not give the main speakers some relief where they need it the most. And you are right--it is a new ball game.