Btw, I have already tried this some time ago:
http://originaltrilogy.com/forum/topic.cfm/ANH-R-Stronger-Vader-edit/post/599176/#TopicPost599176
Test video: http://vimeo.com/51940950
But there was no feedback, except it made Bingowings laugh :)
Without a more punchy line from Vader Tarkin's silence is unintentionally funny (well I laughed... sorry).
so I scraped the change and forgot about it.
Now that I am in the finishing stages, I came back to this scene and I think that if I tweak the video idea above, it could work.
I'll will post the new tweaked video of the original cut so Tarkin remains silent, and a version ending with Tarkin just saying "Terminate her.".