dam-buty

I really don't think the Facebook login is a barrier. Most people have it, and your audience is probably not privacy-anxious hackers but rather happy-go-lucky social media users. I wouldn't bother too much about it.

Adding other social logins, though, would be a good idea. And Github is now an id provider, so why not integrate that? Surely the startup community would feel less blocked by this :)

It may depend on how you define local. For example, when i lived in Mexico, "local" news for me might have been news from my hometown in France, but GPS location would not let me see that.

Also, you might wanna consider the middle ground of just using "coarse" positioning, which is all you need to identify the city. GPS sensors cost an awful lot of battery life and should only be used for apps that need precise positioning, imho.