So Armageddon has now been rumoured for a while now that it'll be replaced by an Avengers attraction so I decided to just randomly think of what could work.
I know that by the time the attraction opens Avengers 2 will probably be on Blu-ray already but I think I have a good idea based off a scene from the first film.
The general idea is that the main room is the control room on the huge boat/flying contraption thing. The effects would show off the attack sequence from the first film. You could have areas where explosions are going off, an effect showing an arrow or two being shot across the room and maybe the whole room (or at least floor) move as if the ship is out of control.
The new pre-show video could be Samuel L. Jackson reprising his role as Nick Fury, informing you that you are the new recruits for S.H.I.E.L.D. but warns that an attack is imminent (or something).
I'm not really sure if the main room would even be big enough to accommodate that sort of room scale but in my eyes it could work and the effects would be easy to pull off considering what they managed with Armageddon.