Microsoft's most recent update to its mobile OS added lots of nice features and opened up some of the hardware limits that previously restricted WP7 devices. Unfortunately the biggest problem for Windows Phone isn't Windows Phone, its the missing applications. Microsoft and their cheerleaders will tell you that 98% of the 100 most popular apps are already on the platform. The problem is that 98% of the remaining app catalogue is missing. And whilst there are usually equivalent tools, for some services there can only be the official app.
Most banks apps are missing. I would strongly recommend avoiding any unofficial banking apps - unless you like losing all your money of course. There are other areas where there are gaps too - and lots of them.
Its a long tail problem - of the million or so mobile apps in existence about 1% ever achieve wider public recognition, Angry Birds is the current poster boy. However the real meat of the problem for Microsoft is that there are apps out there that don't have huge followings - maybe even a few thousand downloads each - and don't show up on anybody's radar. Except there are thousands of them and for each one there are users for whom they are absolutely crucial. Their absence in the WP8 store makes it impossible for these users to jump platforms.
How can Microsoft resolve this? Well there's been a slow, steady growth in the number of Windows Phones apps being published, but its not going to be quick enough to keep Windows Phone relevant, no matter how good the hardware (and credit to Microsoft's partners there's some pretty good WP8 hardware out there). Unfortunately for Redmond there's no easy way to speed things up. The work its doing to court developers is good but now it needs to identify those core applications that haven't been ported and put its own money and developers onto the task. I'm sure the banks won't turn down a free Windows Phone app if Microsoft write it for them. The BBC clearly struggle to support anything but iOS, but a little assistance from Microsoft's developers would probably grease the wheels and result in a (much needed) iPlayer for Windows Phone.
Its going to be more short term financial pain for Microsoft but if it intends to maintain a mobile platform its pain it must suffer to survive.