The main problem with WP widgets, and with all widgets that other people build that are based on the WP widget model, is that there are no filters or hooks inside the widgets to make modifications. I’ve had the same problem with existing widget code and making modifications and I almost always end up building my own custom widgets because it’s practically impossible to easily make changes to the existing ones.
Widgets aren’t overly complicated, you might even be able to convince the author or the one your using to add some hook so that you can filter the widget args. Maybe a filter that passes the arguments so that you can modify the before and after widget settings.
