Ragnorak: Yes, it should be good business for them with so many Whatsapp users being forced to upgrade. I'm still sticking with BlackBerry for my primary phone though, will just use the Android apk for Whatsapp on my BB Classic when the time comes, the same as I do for Skype. Another option for keyboard lovers is to get the BlackBerry Priv or wait for the upcoming BlackBerry Mercury, both of which are Android phones.
On a positive note, according to the Whatsapp blog BlackBerry and Symbian S60 users have been given a reprieve until June 30th 2017, so maybe Mark Zuckerburg and co are listening to criticism.