the only worst part in cortana is the weather layout, it should have had some background image or color atleast, btw an animated weather icons would have been awesome..and the font active tile of cortana should have been reduced a bit...
I'm not a designer, but here's my thought on it:
Animations and backgrounds? Right now it presents you some basic information at a glance (along with the other info displayed there) and tapping on an item takes you somewhere to get you more information. Tapping on the weather opens the weather app where you have all the fancy visuals and details. I don't think trying to pack a bunch of detail, animations, backgrounds, etc... into the Cortana window would help if the point is to present you relevant information on various topics. Keeping the view clean and simple allows you to see what you need to see at a glance, and then if you want to do something simply tapping on that item takes you into the appropriate app with more detail.
Regarding the OP and the pivot idea, that seems to make sense if there are multiple items per view, but in my experience with Cortana thus far it looks like more often than not there is only a single item that would belong in each view. For example right now Cortana is showing me traffic info for my trip home, weather, and top stories. If each item were in a categorized pivot then I'd have 3 pivots right now with only a single item in each of them (and that's counting on the idea that pivots with no information at that time would be hidden.) Also, doing so would require extra screen space to be used for the pivot titles in addition to the Cortana circle, music icon, and notebook icon that already exist at the top. Adding that up there in addition to the items that are already displayed would take up nearly 1/4 of the screen by my quick measurement (assuming the titles are of similar size to other pivot titles in the OS.)
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