I was on a (p)review team for a short-film festival for a number of years. I learned a lot about what makes a video appealing to me, roughly in order:

1) Sound! Bad sound can ruin a video even if everything else is perfect.

2) Editing is key, we rejected a lot of 10 minute films that could have been turned into great 2 or 3 minute pieces.

3) A good story trumps a series of pretty pictures

All of these are big problems for quickie mobile videos so I think tools for sound and editing could really help.