FWIW, I have yet to see many
great Trem movies.
Tremulous Promo II is pretty much the only one worth mentioning. And that came out in 2006. Sorry if I'm missing any others.
What makes a video good?
* It should be short (around 3 minutes or shorter).
* The rhythm of music should go well together at all times with the flow of the scenes.
* You can't just throw together action scenes and hope you get a good video, you'll only get random scenes put to music. You need to think about the flow of the images.
* The video should have a message. Either one that derives from the music, or "trem is cool", but it should be something that is passed on to the viewer, a mood, a feeling if you want.
Look at the video I mentioned: it has a balanced mix of both alien and human point of view, it has spectator fly-by's, it has building, slow motion and time-lapse scenes, taunt animations, captions etc. A good video takes a director and good editing, not just cut and paste.