Summary
User-centric services such as OpenID, Microsoft's CardSpace, Sxip, YADIS, and so on improve the online situation by eliminating the need for remembering tons of passwords. Authentication-wise, they can also be pretty secure—if the user is required to log in with a one-time password, for example. However, once an identity is compromised, the game is pretty much over because attackers have full control of the victim's online experience. This is not that easy to achieve with the directory-centric architecture on which most web services are based today.
Attackers can compromise one account, but they cannot automatically get access to everything the victim has. Identity 2.0 services are definitely the way forward. The next step is to find a way to secure them.