I have noticed some trends/interesting things relating to aos and miniature battle report in general on youtube.
Getting battlereports on armies that have been just recently updated or released seems to help getting noticed.
RULES getting them right is important on battle report, huge rules error can ruin wieving experience especially if it affects the outcome or the game.
Personality is really important, people need to enjoy your voice and presentation style.
Visual beatiful armies are just sweet for the eyes, also different angles for awesome scenes on the battle field is nice to see mid battle report (striking scorpion does that in their report tho they are 40k)