Showing off the Jackal is always a plus, it's probably the coolest of all of the mounts in my opinion, maybe you could even show off the different skins for the mounts. My favorite part of the trailers is that quick scene where Joko's and Balthazar's minions are charging into each other, it was also used in a previous trailer for maybe a second longer. I think though I've just always been a fan of watching scenes of large battles in game going back to GW1 when you could play the story of Turai Ossa and watch the massive battle unfold in the background.