Do you find the slowness / bugs only with Office products? I believe that Office does not use the standard clipboard until one has switched out of the Office program. I remember reading about an Office clipboard that keeps a history of clips and has some additional functionality over the standard Windows clipboard.
If this is the case, then perhaps Office has some event notifications about its internal board that could be used to improve performance in Office. Did you talk with the add-on developer about issues in your versions of Office?