The reason why we couldn't complete the interface on Windows Mobile 6.5 is because of time. We only spend what, eight months, nine months, to build 6.5 from ground up and it's actually an amazing engineering feat. But, in order to do that, we had to do some prioritization and we had to cut certain features. Eventually, we will make sure that the UI capabilities are carried out throughout the whole platform.
Rumors about Windows Mobile 7 have been swirling for at least two years and has been seen as the OS to get the mobile platform more competitive with consumers. Thanks to the iPhone, Windows Mobile is seen as relatively user unfriendly. The iPhone showed what a real mobile browser should look like and for most of the world, removed the need for a geeky looking stylus forever. WinMo 6.1, the currently released version, still requires a stylus for its touch screen devices to hit the small icons and app controls or to easily navigate the menus.
By now you've seen images of WinMo 6.5 with the honeycomb interface and large menus designed for pudgy fingers. It is clear the iPhone has been a major source of, uhm, lets call it inspiration, for the platform. But by Microsoft's own admission, this isn't where they want to be. They just ran out of time.
In fairness to Microsoft, they continue to have to deal with something that Apple hasn't with the iPhone, and that is an existing large userbase and thousands of applications. When the iPhone came out in 2007, they had no compatibility issues to worry about with applications or drivers. In fact, they didn't even support native apps on the ordinal device. It didn't matter what the UI was, it wouldn't break anything. Microsoft deals with this all of the time on the desktop side. Compatibility issues were probably the biggest reason people avoided Vista. Windows Mobile has sold tens of millions of devices in recent years and there are thousands of applications and peripherals. With each new version of WinMo, some of those apps and drivers get broken, but MS goes to great lengths to maintain compatibility. Those efforts though slow down the pace of innovation, and it really shows in WinMo 6.1. Even though the iPhone is about to hit 3.0 this summer, the basic UI hasn't changed in two years, they have just added more features.
It still is frustrating for users though that have invested resources into Windows Mobile to have to wait. 6.5 will give some relief, but 7.0 is what we are really waiting for and that is over a year away. We already know the upgrade story on 6.5 - some 6.1 devices will be upgradable to the new platform, but it is up to your carrier to provide it, something they seldom do. If you buy a 6.5 device, will it be upgradable to 7? Perhaps, but chances are slim, as they always seem to be.