System or Atom?

I was very excited to see this book recommended to me, as I have been thinking along these lines for a while now. I agree with Richard Cronin’s critique of much of evangelical assessment of Rome. It is too atomistic. It has a tendency to miss the forest for the trees. It argues about admittedly centrally important issues without, however, getting at what makes Catholicism Catholicism. I also have a hunch that this might be behind Bryan Cross’s repeated charges of begging the question. Because the hermeneutical, systemic, presuppositional issues have not been dealt with yet, it is somewhat futile to argue about individual issues. Now, it is not entirely fruitless. There are still aspects of the argument concerning justification, say, that can be addressed without reference to the system as a whole (I think in particular of the exegetical questions). However, this kind of critique will always run the risk of distortion. According to the description of the book (I haven’t read it yet, but hope to soon), the systemic issues concentrate on nature-grace and on ecclesiology. I wonder at this point what he means by “ecclesiological self-understanding.” I think that this could be a very helpful way of describing the center, as long as it does not leave out what Barron calls his incarnational understanding of the church. I also wonder how he will argue that the nature-grace issue is a systemic issue, and not simply another issue in a long list of issues. I guess I will just have to read the book and find out. To my Roman Catholic readers, how would you describe the centrality of Roman Catholicism? And where have you found the best descriptions of that centrality? Would you agree with Barron, for instance?