As a few here have said, Windows Phone will not take over in the sense of popularity. They may take over is some segments of the mobile community, like business, due to the Outlook/Exchange and Office integration.
Some of the plusses of Windows Phone to me including the integration of Office (mentioned above), Xbox, Zune, Skydrive and Exchange.
A lot of Pocket PC users probably are not jumping on the bandwagon yet due to other issues like handwriting recognition/input, as when I had one, that was what I liked about it as well. The ability to take handwritten notes was a major plus for quick notes or reminders. That must be why I like my Galaxy Note so much.
Microsoft stuck with single core processors and lower spec hardware at first for a few reasons. One was cost, to keep the prices of the phones down. Also, it was a way for developers to write apps for the devices that would work across multiple carriers and devices with a minimal set of hardware specs. In other words, if the app works on this device, it would work on all devices. Developers could also unlock and use their own devices for testing.
With Windows 8 coming, Microsoft needs to be thinking about boosting their hardware specs to keep people interested in the devices. I have heard rumors of them going to dual core processors for 1080p video, and to help with processing functionality. This being said, Microsoft has said that their OS works extremely well on a single core CPU, so who knows what we will see until they release it for the masses.