According to the writers at BotCon last year, Barricade didn't die because his decapitation scene didn't make it into the final cut of the movie. It isn't known how far it got to being included (filmed or animated), but must have been late in the post production process, because his death was still in the comic (which was written to closely match the script). It means that the comic universe (Barricade dead) and film universe (Barricade alive) are now two distinctly different universes.