Personally I like WeChat's approach: Messaging feature and social feature integrated in one app, with messaging as the default view when you open the app.

Facebook is actively separating messaging feature from the main app and force users to use two different apps, which is inconvenient IMO.

Maybe it is just a legacy issue where Facebook started as a social media whereas WeChat started as a messaging app, but I am interested to see if Facebook would be better by prioritizing "messaging" over "feed".

(Disclaimer: I am a Chinese user.)