Center channel phase question.

The front speakers should all be the same distance from the seating position. If the Center speaker is closer, the processor can delay the timing. Typically its 1 millisecond per foot. If you can set them equidistant with no adjustment, that is ideal.

"Another question just popped in my head. How many 1) actually follow this concept; 2) have ideal room setup/situation (unobstructed and equidistant); and 3) are willing, better yet know how, to adjust the processor to compensate for the setup shortcomings?"

I actually did design home theater cabinetry in this way. Protruding columns move the LR speakers close enough to for the correct arc. Also, this can be done with theater "screen walls" made of black acoustic speaker grille fabric. A fixed screen floats on the center of the wall. Behind the "screen wall" speakers can be set on stands and moved about as desired. If the speakers are set proper then timing, phase and level require little or no adjustment.