Hi!
Anomie, bd808, CSteipp, and myself have been working on updating Tyler's previous AuthStack RfC: https://www.mediawiki.org/wiki/Requests_for_comment/AuthManager.
Our goal is to build an authentication system that is flexible enough to support the variety of usecases that MW currently supports and those it should support in the future, without requiring tons of hooks or ugly hacks.
Please leave comments and feedback on the talk page :)
Thanks! -- Legoktm