@Bass: My take on this is they will not port the desktop shell to the PI for some of the same reasons that RT crashed and burned.
Zero of the currently deployed software will run as it will have to be re-compiled as ARM. Yes, you could run some windows store apps, buts lets not even bother with that as there are so few.
Driver compatibility. Again while there is promise of the support of the entire windows driver eco-system and the Windows Universal Driver Model, but again there is near zero not-in-box support of this until the OEMs recompile and re certify their drivers for ARM, as evidenced by the fact there is not even WiFi support on the pi image yet.
More likely will be a third party BSP being released to support porting of the Windows Mobile SKU to the Broadcom BCM2836 SoC and hence the raspberry PI, this would get you a shell (tablet launcher, basically the start screen from windows phone) and support for Windows 'Metro' and UAP apps (i.e. windows store and windows phone) and Continuum support. Legality of distributing a full OS image based on this is another question at this point.
As the team that is doing the 'Windows IoT Core for Small Devices' port to the Pi is called the 'self-enablement' team, I'll let you extrapolate where this is going.
Personally I'll stick to one of the excellent Linux distros for the PI when I want a desktop OS on it, and use the Windows IoT OS when it makes sense.