They might as well do it now...they can't really lose much, only gain, as they practically own the market for WP!
Although, it is one aspect I believe Microsoft has not acquired...the Nokia software division!
But then even more reason to expand it because the handset division no longer affects them...well it won't soon at least!
I mean they already have the app available on every single Windows 8 Pro & RT device...although I suspect had they have released their RT Tablet before the app...the same situation as WP would be going on!
In my opinion...TIME TO GO CROSS PLATFORM!!! It's a worthy service that is differentiated from other similar services around!
+1020