One thing I think they should address in the next trailer is to promote the villain. Marvel's biggest weakness is throwaway villains like Whiplash, Malekith and Ronan. This trailer didn't even feature the villain apart from some random shots of Corey Stall looking like Lex Luthor with no dialogue. They've had awesome success with Loki and Winter Soldier and Ultron looks incredible. They should put some Yellowjacket into the next trailer. Show the threat. I get that this is just a teaser though.