Microtonality: Off the Grid/Out of the Box

Like the streets of mid-town Manhattan, equal temperament was conceived as an idealized grid in which everything is evenly balanced and self-contained. But straight lines and equal increments are rare in nature. And the return of non-tempered tunings has opened exciting new possibilities for moving Western music off the grid and out of the box.
In equal temperament, all pitches are theoretically alike. So it’s easy to treat them as abstract entities (“notes” rather than tones) and to lose touch with their sounding reality. By contrast, in tunings based on the whole-number relationships of the harmonic series, each pitch and each interval has its own unique identity.
In his insightful Music Primer, Harrison observes that Schoenberg’s excellent ear lead him to understand that in equal-temperament all intervals of a given type (except the octave) are equally untrue, making all the pitches of the chromatic scale essentially equal. In this light, it’s not too hard to imagine Schoenberg’s twelve-tone technique as the musical equivalent of grid-lock. Rather than sit stalled in a dodecaphonic traffic jam, American composers (many of whom have felt less of an investment in equal-temperament) have chosen to retune.
Do tunings grounded on the harmonic series represent open roads, leading music out into new country where it wants to go?