If you went into a server, went obs, and recorded tons of demo footage you would have plenty of good material to piece together for a promo video. It would all be in small demo files from which you could pick out three second clips to put together.
If you don't know, I read somewhere on a movie making site a while back that the average length of a continuous clip should be no more than three seconds unless you are working a specific shot or slow motion clip.
It's all about your creativity and choice of shots. I could go into a server with 100% 2 week playing nubs and record the action and piece out enough clips to make a good promo, short of catching fancy jumps which shouldn't be too highly focused on in a promo anyways.
Creativity and emotion. A promo should draw your audience in. In DP the look of the game is not going to do that very well so you have to depend on creativity and emotion. Play off your soundtrack. Don't just select a soundtrack and run a string of clips together. The emotion of you clips should match the emotion of your music. So selecting a music that varies in emotion is crucial also. You don't want to use something that is hammering from beginning to end, or something that is elevator music either.
Here's an example of my layout. Most of this is for the PBCup promo video that I have yet to do. I have sort of modified it a bit adlib style for this thread.
First download this song:
http://lords8n.zilla-clan.net/music/hardnbizzy/Vivaldi_Winter_Concerto.mp3This example is completely built around the music. The music dictates the mood. You are pretty much forced to the mercy of your music unless you are talented enough to create your own music built around a planned clip sequencing.
This is the Vivaldi Winter Concerto. It starts off very slow and continually builds in energy until it is absolutely ripping your face off with energetic violin.
The story board goes as follows (play the tune along with it and you can get the idea of its movement):
00:00 - 00:38: Logo fades in followed by various information about the event showing in succession in tempo with the music. This is intermixed with still action shots in-game. Towards the end the screen fades to a still shot of a section of a map where you would normally see heavy positional fighting. This shot has no players in it, just the area of the map fading to the same area from different angles.
00:39 - 01:00 Following off of the area shots from the end of the previous time slice we switch to the exact same style of shot switching on that same area, only in these shots, during this up tempo music, there are people in the still shots engaged in fierce battle. These can be still shots, or a form of circular panning shot around the area. With each cycle of soft to up beat, of which there are only a few, a different map area of a different map would be used.
01:01 -01:15 This time slice falls off of the last up temp section into another slow section that continually builds for 14 seconds. During this time slice we will show more of the area action stills, but in a succession of closer zooming in on players till we are zoomed up right in the face of a character in a dramatic building climax.
01:16 - 01:27 High energy section of non-specific action sequences. These clips are general in-game fighting in relatively large area not focusing on any individuals. Maybe some multi player DM clips of total carnage.
01:28 - 01:50 Intense violin section. More in game action shots. Only now we switch to focusing on very specific sequences. A particular burst through a defensive line. A person on rampage eliminating multiple enemies. An amazing flag grab or cap. Anything that appears to be an amazing play.
01:51 - 02:09 A fall off in energy at this section with some of the same style action shots, but freeze framing the action at a significant point in sync with the music fluctuations. For instance, A person has the flag and is making a run for base only to come around a corner and be ambushed, freeze framing on the exact moment a paint ball hits him.
02:10 - 03:06 The music enters an approximate one minute lull. During this section we will show some other aspects of the game mixed in with various information texts. Some of the stuff we can show here are dropping and picking up a gun. dropping a flag as a team member picks it up. Anything about the game which is critical, but not necessarily action based. The key being to display textual information while showing some of the lesser exciting portions of the game itself.
03:07 - 03:30~ The Grand Finale. This will contain the most hardcore action shots of all. The most amazing stuff will be saved for this section. This section fades out to silence and should be created with a dramatic fade ending.
So there it is.
I think, however you approach it, you should first storyboard your project as I have done above. Doing so, and posting it for others to view, will let everyone know what your intent is, get you valuable critique before you put in a lot of hard work, and give your actors (if you use them for specific clips) an idea of what you are after.