Prior to 1960, the diaconate functioned largely as a terminal ministry for women and a long-term holding pattern for racial minorities. After the mid-60s, deacons were reframed as having a role representing Christ in a way that functionary priests do not.
Ideally, the parish priest neither sits back, nor stands in front, but rather nurtures the laity to take broader leadership roles, while paying attention to the needs of the whole flock.