Allow name in unregister_sidebar_widget()

Would be nice if in the unregister_sidebar_widget() would accept either an ID OR a (class) name of a widget, as some of the other widget functions do.

This would be useful if in your templates you want to unregister all instances of a particular widget (rather than just a particular instance, for which you knew the ID).

For instance: you want to disable the Recent Post widget only in the homepage template (since it would be redundant).