In light of the newer global authentication, does it still make sense for each StackExchange site to maintain its own Open IDs? Why not have one pair of OpenIDs for all SE sites?
The most obvious ramification of the current behavior, and the most likely to affect users, is that alternate OpenID is not copied to new SE site profiles when creating associated accounts.
But it's also possible to do strange things like have SO account with open IDs OID1 and OID2, Programmers account with OID2 and OID3, and AskUbuntu account with OID3 and OID4. And they're all linked, but the automatic login detection doesn't seem to work in all directions (when I go to AskUbuntu I'm not recognized).