IMHO the gyro is a reference used for lots of things, and it should be set to indicate airframe deck angle relative to the earth. If you have to struggle to remember that a zero climb angle is 2 degrees up or down from the big lateral line, well, that's why they pay you the big bucks. You don't adjust the natural horizon when you fly VMC, do you?
If you mess with the ADI, you end up not knowing where you are, and that might make a difference when you need to know fuselage angle. Flare attitude comes to mind as a nice to know absolute, as does slope angle. Mess with the ADI and these are not knowable from the display.
Intelligent seatweights, Sasless! I like the term. How about naming pax Screaming Ballast?