BlackBerry 10 marks a milestone for RIM, and also a chance for the company to reinvent itself after some difficult and downright horrifying times. A mobile platform lives and dies based on the apps and developer community surrounding it. RIM might have lost a big name already, before their newest phones are even on shelves.
After an email from Crackberry author James Richardson, WhatsApp's team confirmed they had "no plans to support BlackBerry 10 at the moment". While it isn't stated, that doesn't mean they're never going back to BlackBerry handsets.
WhatsApp makes sense for cross-platform communication, and it arguably makes the most sense with a BlackBerry. After all, the physical keyboard has long been a defining element of RIM design. BlackBerry Messenger is also established, being one of the major selling points for the phones.
Another quick and dirty fix is to sideload the Android APK. Richardson mentions another BlackBerry user identified as "Bla1ze", who sideloaded the APK to a phone and was thus able to continue using WhatsApp. While it's hardly a permanent solution, it works... for now.