Actually, this might be the best they can do.

You probably thought that the newest trailer for Avengers: Age of Ultron couldn't get any better than it already is. Foolish human mortal! You did not consider the possibility that Mashable would call upon the vocal talents of Vine-lebrities Arwen, Leia, and Neo to redub the the trailer, replacing all the uninspired adult voices with superior child ones. This new version will rule the world! Muahahahahahahaha!!!

Oh, and this version here, with all the voices gender-swapped, will serve directly at its side:

Sources: The Watercooler | h/t Tastefully Offensive | KOOL 96.5 | h/t Laughing Squid