In order to ensure that the document looks as close as possible when viewed in the editor and in a browser after export, all properties are exported explicitly. We have considered adding customization options that will allow the export of "cleaner" HTML. Unfortunatelly, this hasn't been sheduled yet, so I can't engage with a timeframe.
However, RadRichTextBox is easily extensible, so you can implement a custom HTML format provider with such functionality.
Excuse us for the inconvenience.
the Telerik team