Thanks for clarifying the Google stuff. We're definitely keeping an eye on them and excited about some of their changes. We continue to the G+ will be a huge player in the social networking scene, but aren't there yet. (Obviously they are there, but we try to look through the eyes of users that would want that option on their site, and right now, they haven't fully hit that threshold).
As for the SCLogin module, for now at least, there will not be a 'basic' authentication for social networks. If you don't have our social networking extensions installed, the SCLogin module would just get you a fancier Joomla login module with easy flexibility to upgrade to social networking integration through JFBConnect/JLinked. That's definitely open to change as things evolve. For now though, our authentication is so baked into JFBConnect, it'd be difficult to break out just a portion for 'basic' integration. Additionally, modules don't have database tables to store the data we'd need.. so to do even basic authentication, you really should have a component just for that. Ironically, in the Joomla world, sometimes it gets complex to make things simple.
Obviously, we're evaluating things on the fly and have plenty of changes in store for the future.. but for the immediate release, that's the plan.
Hope that helps,
Alex