Understanding what is Android and what is not
"One reason is weak integration with social networks: the photo app doesn't offer a share to Twitter or share to Facebook option until those apps are installed."
As far as I'm concerned that's the app done right, and isn't a Samsung failing. The 'Share' function is part of Android, and relies on apps telling it you can share via them - meaning you can't share via an app that isn't installed.
Much better than baking in sharing options that may/will stop working when the social network either changes it's API or disappears.
If you are going to review a phone, at least understand why it does things, and who is responsible.
P.S If i'm talking rubbish, happy to be corrected