Why should I quit WhatsApp? It's straightforwardly easy. Although Facebook said they'd keep both companies separated as completely different products, their message after the acquisition was something like "WhatsApp is on a path to connect 1 billion people" . So, this is Facebook lying, once again.
So yes, I'll delete my WhatsApp account within the upcoming days and switch to (or keep using) Hangouts. And I'll probably end up deleting my FB account as well.
No more questions, your honor. Move on.