Inserting the complete address requires the URL to be parsed. In other words, the video's unique identifier has to be extracted in order for the correct embed code (which actually inserts the video player in to the post) to be generated. I'm using vBulletin's default BB code function to insert the embed code (I explain why below), and unfortunately it does not allow the use of regular expressions to parse text strings enclosed in tags. As a result, us humans have to do the manual parsing instead of the server.Why not allow the full URL to be used with the tags too?
I'm not sure which plugin you're using, but there are new plugins which do provide the extensive parsing functionality you may be looking for. I am not using a plugin to display the video here because of the long-term sustainability (or lack thereof) of privately maintained software modifications. New versions of vBulletin come along all the time, and I don't want an upgrade to break what has become an important and often-used feature of the site. Using vBulletin's included BB code is future-proof.
No, the Quick Reply box buttons can not easily be modified.
