It's only the official thread on WPCentral, it doesn't mean that the WhatsApp team use it as a official platform to communicate with users.
Chill guys, they will release the update when it is ready and if you've ever worked on large development projects you'll know that that can mean anything from a couple of days to months before the application is ready to be released to the general public.
The beta is there to test beta code which has known issues and therefore cannot be made available to the general public as it will cause more headaches for their support than what it's worth.