Don't give me the lecture that it will be alright just like Facebook Newsfeed and Timeline redesigns! It will not, most likely because, if we have to open another new app for chat/msz it will not be Facebook Messenger. For me I will prefer Viber, others could prefer Skype, WhatsApp, Line, Kik or even Google Hangout, but it will be hardly FB Messenger! I am also downloading it, so I could give one star, and what if Facebook loose some mainstream user in their main app after this move? There is no ads in Messenger yet, and it will be hard to add one.
Read the Mashable coverage on how “Facebook Messenger” now No.1 App in App Store with just 1 Star (lowest possible) rating!