I've been using the preview since it was released, and there're some things that became worse than Windows 8 IMO.

While I understand it's just a preview of the blue update, I'll list some points here, wishing for the best in the final release:

1 - Performance Information and Tools: this item doesn't exist anymore.Though what it did was only gather useful tools in one place, a cool feature that was available in that section is the "Windows Experience Index", also not available from "This PC"'s properties

2 - Animation when going from Modern UI apps to Desktop apps.That animation can be seen in Windows 8 when the Modern App does something that calls a Desktop app.For example, you open the Modern version of Internet Explorer, and then select "Page Tools" > "View on the desktop", or simply open an attachment (that's associated to an Desktop app) in Mail app.
That was a cool visual effect, but it's not there anymore.

I hope these itens make their return in the finished update.

Thanks for your suggestions, I will record them.