An excavator comprising a machine chassis, an excavating linkage assembly, a rotary excavating implement, and control architecture, wherein: the excavating linkage assembly comprises an excavator boom, an excavator stick, and an implement coupling; the excavating linkage assembly is configured to swing with, or relative to, the machine chassis; the excavator stick is configured to curl relative to the excavator boom about a curl axis; the rotary excavating implement is mechanically coupled to the excavator stick by the implement coupling and is configured to rotate about a rotary axis R different from and intersecting the curl axis such that a leading edge of the rotary excavating implement defines an implement heading / at least partially based on an implement heading angle θ I measured between a heading vector of the rotary excavating implement and a reference plane that is perpendicular to the curl axis; and characterized in that the control architecture comprises one or more dynamic sensors (40, 45), one or more linkage assembly actuators, and one or more controllers programmed to execute machine readable instructions to utilize position signals from the dynamic sensors (40,45) to generate a position of the leading edge of the rotary excavating implement relative to an obstacle reference, at least partially based on obstacle reference data from a grade control database, and map information from the grade control database, utilize implement edge signals from the dynamic sensors (40, 45) and the position of the excavator relative to the obstacle reference and the map information to generate a nearest implement edge signal indicative of a position of a nearest implement edge of the leading edge of the rotary excavating implement relative to the obstacle reference, and utilize the linkage assembly actuators for divertive rotation of the rotary excavating implement about the rotary axis R to adjust the implement heading Î, wherein the degree of divertive rotation about the rotary axis R is sufficient to account for divertive rotation away from substantially all of an actual or projected overlap of the nearest implement edge with the obstacle reference. the excavating linkage assembly comprises an excavator boom, an excavator stick, and an implement coupling; the excavating linkage assembly is configured to swing with, or relative to, the machine chassis; the excavator stick is configured to curl relative to the excavator boom about a curl axis; the rotary excavating implement is mechanically coupled to the excavator stick by the implement coupling and is configured to rotate about a rotary axis R different from and intersecting the curl axis such that a leading edge of the rotary excavating implement defines an implement heading / at least partially based on an implement heading angle θ I measured between a heading vector of the rotary excavating implement and a reference plane that is perpendicular to the curl axis; and characterized in that the control architecture comprises one or more dynamic sensors (40, 45), one or more linkage assembly actuators, and one or more controllers programmed to execute machine readable instructions to utilize position signals from the dynamic sensors (40,45) to generate a position of the leading edge of the rotary excavating implement relative to an obstacle reference, at least partially based on obstacle reference data from a grade control database, and map information from the grade control database, utilize implement edge signals from the dynamic sensors (40, 45) and the position of the excavator relative to the obstacle reference and the map information to generate a nearest implement edge signal indicative of a position of a nearest implement edge of the leading edge of the rotary excavating implement relative to the obstacle reference, and utilize the linkage assembly actuators for divertive rotation of the rotary excavating implement about the rotary axis R to adjust the implement heading Î, wherein the degree of divertive rotation about the rotary axis R is sufficient to account for divertive rotation away from substantially all of an actual or projected overlap of the nearest implement edge with the obstacle reference. utilize position signals from the dynamic sensors (40,45) to generate a position of the leading edge of the rotary excavating implement relative to an obstacle reference, at least partially based on obstacle reference data from a grade control database, and map information from the grade control database, utilize implement edge signals from the dynamic sensors (40, 45) and the position of the excavator relative to the obstacle reference and the map information to generate a nearest implement edge signal indicative of a position of a nearest implement edge of the leading edge of the rotary excavating implement relative to the obstacle reference, and utilize the linkage assembly actuators for divertive rotation of the rotary excavating implement about the rotary axis R to adjust the implement heading Î, wherein the degree of divertive rotation about the rotary axis R is sufficient to account for divertive rotation away from substantially all of an actual or projected overlap of the nearest implement edge with the obstacle reference.