I think the biggest problem with FB right now is the way they force groups content into your feed. It's way, way overdone. Back when people joined those groups they were smaller and more focused and people were hoping to get occasional updates on some topic they're interested in.

Now it's at least half your feed if you don't trim the groups and your actual friends get lost in the noise. I'm sure FB has some data about engagement or some such, but they should remember why people use their service and refocus.