Remember when they changed everyones default email to be username@facebook.com? Yeah, thats pretty much all you're going to get from the API.
To me as both an app user and developer, single sign on feels like the Right Thing To Do. I'm sick of running through the same sign up flow for every single service I use, like a hamster wheel. Maybe the solution isn't fb, it's some kind of apple or google SSO? Why aren't AAPL and GOOG pushing their own SSO hard on the mobile ecosystems they control?
The solution is definitely not Facebook, Google, or Apple. They all plugged SSO into an existing platform and allow developers to perform actions on my behalf with the same credentials. Sadly, Microsoft's Passport.net was the closest anyone has gotten to a real solution because they treated their own properties as just another consumer. They killed that by trying to tie it directly into your Windows login which are inherently insecure.
because neither of them has a controlling amount of the required market (which is basically the entire internet!).
Mozilla has a project called persona (http://www.mozilla.org/en-US/persona/), which aims to solve this by splitting the login from verification and authentication, but preserves privacy (unlike oauth). If vendors of services can give up their desire to control the userbase, this could be the solution.