Nobody knows the strategy of WhatsApp developers...its been almost 4+ months n everyone comments"coming soon"...or it will b coming sooner than later...I think those people have no accountability whatsoever they do.
well, think from thier point of view, they are mostly developing for IOS and Android cause they are probably around 90% of the market.
using as much resources as 45% [IOS or android] for a 10% Operation system, its seems not to worth their time THAT much. but ofc, its still worth it somehow, but not as much as others.
now facebook bought whatsapp and microsoft is working with facbook on whatever, such as the facebook application, is now working with them on the whatsapp too [for the WP]
its true that its was bad to announce "Coming soon", and you can be mad at them for it, but it was really looks like it was coming soon, WhatsApp team have his issues.