Indeed, copy/pasting rich text (images, tables, formatted text) from an external source to RadRichTextBox will not work. The reason for that is Silverlight's limited clipboard which supports only in plain text. Unfortunately, this is a limitation of the platform so there is nothing we can do in this regard.
About the problematic copy/paste form word to RadRichTextBox under WPF - could you please open a support ticket and send us a sample word document, so that we can reproduce and investigate the problem.
About the problem with the input with the Chinise IME, we would appreciate if you could open a support ticket for that as well. It would be helpful to share some more information about which IME you are using and what is the errors(if any) that you are getting.
Thank you for your cooperation.
the Telerik team