Where I come down is that the diversity of Christian communities must be, at least to some significant extent, the intention and purpose of God. Human beings being what we are we need both diversity and connection. We need both to be healthy. Maybe it's like the needful variety in a gene pool that species need to survive. In ways that seem paradoxical, perhaps, Catholics and Protestants need each other (and neither would be what we are, at our best, without the other). For that matter, both Catholics and Protestants very much need the Eastern Orthodox, as well (and that need is mutual for them, too, I'd say).
I'm not talking about establishing some sort of least-common-denominator religious mush (even though some of us, such as myself, exhibit some interesting combinations of perspective). I'd say that within a context of historic Christianity there are parameters. But with charity, full candor, humility, and integrity in faith, somehow, by the grace of Christ we help keep one another at our best. The sad, too, too many cases of sinning against one another are demonstrations of our not getting it.
Oddly enough, my ecclesiology is strongly influenced, Protestant that I am, by Eastern Orthodox Trinitarian theology. In terms of my doctrine of the Trinity, I'll always be more of a Cappadocian than an Augustinian. There's a good article by the great Russian Orthodox theologian Vladimir Lossky (included in his anthology In the Image and Likeness of God) that is rather to the point. The tendency of Western Christian theology, he argues, is to subordinate the eternal distinction of Persons in the Holy Trinity to the unity of the Godhead. Eastern Orthodoxy, on the other hand, keeps the unity and distiction on a theological equal par, with considerable implications, as Lossky underscores, for the doctrine of the Church.
My Protestant dimension kicks in with my full confidence that "where Christ is, there is the Church," and my lack of full confidence, however, that one can automatically reverse that formula. For those interested in the Church Fathers, one could say that I almost turn the ecclesiology of Cyprian of Carthage, for example, on its head.
Regards.
