Speculation is that this move enables the Holy Father to create new Patriarchates and thus divide up the West for better governance. For example, a Patriarch of Africa, a Patriarch of Asia, a Patriarch of Latin America, etc.
Honestly, I don't like the idea of new Patriarchates. The patristic "pentarchy" was a disaster waiting to happen. Patriarchs enable large scale schism (e.g. the Patriarchate of Alexandria). This arrangement could also allow the new Patriarchs to team together against the Petrine See, for example, when Constantinople, Antioch, and Jerusalem parted ways with Rome.
But heh, Benedict knows a thing or two more than me about all these things - so more power to him. And if the whole scheme works for the reunion of the Eastern Church, go for it!
This is a picture of Pope Shenouda III of Alexandria and All Egypt. He has real, ultimate, patriarchal power! Sorry, I couldn't resist posting his picture.