Vines are 5.5 seconds too long

I'm not sure why you think your personal preference is optimal in any way. I hated the short clips on your holiday video, and couldn't help thinking that the actual problem here was your (stated) inability to hold a camera steady. I like vine's 6-second clips OK, because that's long enough for one complex shot or 2/3 simple ones. Films and TV often use much shorter shots, but doing so involves preparatory context-building.

Short shots without context are just confusing and frustrating because there's no prior context or established line of action (for example someone on screen left fires a gun pointing to the right, cut to someone being hit on screen right - part of the art of film is to lead the eye around the screen smoothly from shot to shot).