These gatherings tend to be highly regulated, very tightly scripted affairs with little room for freewheeling debate and discussion, let alone actual decision-making. The pope can ignore them entirely, though he usually pays them some selective attention. Still, they are but the palest imitations of real synods, which is a great, and wholly unnecessary, pity--not least because there is no reason, theological or historical, to prevent real synods from functioning in the Church of Rome as happened until at least the twelfth century (a history I recount in detail in my book). Nothing in synodal practice threatens 'papal primacy' but only strengthens it.
The problem with the synod, apart from its unilateral if well-intentioned creation, was aptly described by Yves Congar. His wonderful diaries record in several places his thought that the problem with Pope Paul VI was that Paul's gestures, often dramatic and incredibly gracious and humble though they could be, were totally mismatched to any coherent ecclesiological vision, and as a result the gestures fulgurated strikingly and then faded to nothing as the conservative, stultified, unhistoric, Rome-centric ecclesiological status quo reasserted itself.
Set for release late this year is a new book that proposes to examine the whole history and functioning of the "synod": Ignatius Aniekanabasi Edet, Ideal and Reality of the Synod of Bishops (T&T Clark, 2013), 272pp.
About this book we are told:
The Second Vatican Council envisaged a more prominent role of the synod of bishops in the Catholic church. However, the idea of the fathers of the council never came to full fruition. In this survey, Edet discusses why the reality does not meet the expectations of many of the fathers at Vatican II in terms of collegiality, communion and trinitarian theology. Edet emphasizes that this failure has implications for the church's life and mission. The concentration of decisive authority in the pope and his curia largely undermines the significance of the conciliar teaching on collegiality-dialogue and participation in the exercise of authority in the church. Edet offers an explanatory comparative investigation and evaluation of the Roman Catholic synod of bishops in relation to similar institutions in the Eastern Catholic and Anglican churches, as well as to the reflections on collegiality and synodality in some of the ecumenical dialogues.