It might be, but the old Last Word was basically the reason he was ever being picked. The new Last Word, however, adds more to him from gameplay perspective and actually synergizes quite well with both Curse of the Silent and Global Silence. CotS/LW could be a really good build now instead of the old Glaive/stats carry build. Still, losing the old Last Word is a pretty big hit, but since it was changed to not trigger from items Silencer had already lost most of his relevance.