I think there are a couple tags that could reasonably apply to http://sakuga.yshi.org/post/show/10423/animated-artist_unknown-smears-sora_no_woto that don't exist right now:
"camera_movement" or "camera_rotation" or similar, for a cut where a significant amount of additional keyframing is done in order to show the virtual "camera" moving in some way other than a simple vertical or horizontal translation. These kinds cuts are often done in CG these days, but when they're not they can be really impressive, and I don't think it applies to a large fraction of current material.
"on_ones", for a cut where the foreground/character animation has an individual frame drawn for each frame of video, rather than duplicating frames. Sure, this is commonly seen for quick movements that only last a few frames, but entire cuts done on ones are abnormal, even for sakugabooru content.
Thoughts?