One huge patriarchate or several smaller ones?
Although endowed with no special jurisdictional authority, there are actually five patriarchates in the Roman Church: Jerusalem, Lisbon, Venice, the West Indies, and the East Indies (Johnson, CLSA New Comm 577). In addition, there are perhaps two dozen "primates" in traditionally Roman-rite countries, although they have little to no governing authority as such (1983 CIC 438).
But the reductio ad obscuritatem that befell the western patriarchates (which were originally associated with their strategic locations as the New World was discovered) might have been a consequence of the fact that, when the pope himself is the patriarch in the west, what matters who else might have such a title? But therein lies the point: the pope no longer is the Patriarch of the West.
Might this development over time (admittedly, likely measured in centuries) allow for a redevelopment of a functioning patriarchate system in the West? Perhaps Lisbon's day or Venice's has passed, but what about, say, Mexico City? or Chicago? or Manila? or even (let's really dream) Hong Kong? For that matter, might some currently quiescent primatial sees begin to exercise once again a real leadership role in their nations or regions?
Or are we happy that there are no effective ecclesiastical structures between individual diocesan bishops and the Holy See, save for the bureaucracies of national episcopal conferences?
Update March 23: See also Statement from the Pontifical Council for the Promotion of Christian Unity, and John Allen's perspicacious reports.