Regarding the Drag & Drop: Thank you for commenting on the issues and reporting them. I can ensure you I have contacted our dev team so they could take a look at these behaviors and make them more user friendly.
Regarding the general behavior: You are correct in your observation and I am happy to say that these issues are fixed and will be available in the next Service Pack release which will be release in the beginning of April.
Regarding the styling: RadPivotGrid presents five possible positions and four layout types which total twenty variations of the ConfigurationPanel. The settings could be found under the RadPivotGrid.ConfigurationPanelSettings Position and LayoutType properties. You could manually customize each field section using CSS and specify the desired custom width.
Additionally, I have updated your account by adding Telerik points in sign of gratitude for reporting your suggestions regarding the Drag & Drop functionality.