The Devices and Services Division is responsible for 50% of Nokia's total revenue. The current deal with Microsoft would grant Microsoft exclusive rights to the Nokia brand name and prevents the Nokia group from licensing or making mobile phones using the Nokia name. This may be the end of Nokia's S30 & S40 Asha division as Microsoft may not be interested in making devices that do not run it's Windows Phone Operating System.
This deal would see Microsoft join the likes of Apple who have gone vertical by owning both the hardware and software components of their business and maybe Google-Motorola.
If the low adoption of Windows Phone by other device makers was a problem before now with the Nokia-Microsoft deal, every device makers would definitely shy away from Windows Phone.
More details to follow