The new Dragon Ball Super: Broly trailer doesn't just show off more of the epic action that we're going to get from this canonized retelling of Broly's introduction, it reveals that the entire core backstory of Dragon Ball's principal duo (Goku and Vegeta) is getting a major revision. This new origin story for the Saiyan warriors of Dragon Ball's Universe 7 will hinge on the story of Broly, and the major rivalry that's established between him, Goku, and Vegeta in the film.
In this new version of the legend, Goku, Vegeta, and Broly all seem to be of equal age - three children born at very different levels of Saiyan society (Goku is a low-level warrior, Vegeta the king's great successor, and Broly is the son of a prominent member of King Vegeta's court). The latest Dragon Ball Super: Broly trailer reveals that when Goku, Vegeta, and Broly are just small children they have the traumatic experience of having to flee their homeworld (or get taken) in order to escape Planet Vegeta's annihilation at Freeza's hand.
The key turn in this story may be the scene in the trailer where Paragus seemingly flees from King Vegeta's throne room, after hearing the king's plan to ship Saiyan children out to other worlds, where they can mature as warriors and conquer planets in the name of the Saiyan empire. Paragus is heard swearing revenge against the king for attempting this plan, while vowing to train his son Broly on his own, and make him into a great warrior. In that vow may lay to foundation of this new rivalry between Broly and the Saiyan heroes of Earth.
If you look closely in the first full Dragon Ball Super: Broly trailer, there's a scene in the Arctic when Broly first encounter Vegeta and Goku, where Paragus screams "Do it, Broly!" and sends his son charging in on the attack (with Paragus presumably using the control collar around Broly's neck to direct his actions). When Broly goes charging in, he has one of two targets to pick from, and he definitely goes right at Vegeta, instead of Goku. In the original Dragon Ball Z Broly movie, Broly had longstanding beef with Goku, as Goku's crying kept him up at night when they were both babies in the Saiyan nursery; in this Dragon Ball Super Broly movie, it seems as though it's Vegeta that Broly has the long-standing grudge against - or rather, Broly is the weapon Paragus uses in his own grudge against the Vegeta bloodline.
The lingering mystery here is if / why Broly would have a major rivalry with Goku. Dragon Ball supplemental materials have revealed that Paragus may have been superior of Bardock, Goku's father. It's already confirmed that Dragon Ball Super: Broly is making Goku's Dragon Ball Minus origin story canon, and in that tale, Bardock is one of the earliest to spot what Freeza was planning for Planet Vegeta. While we haven't seen the evidence yet, there could be something that occurs between Bardock, Paragus, and King Vegeta, which would make Goku and equal target for Broly as Vegeta. One thing we definitely know for sure: Freeza has a massive target on his back as well, and Broly's coming to collect!
Dragon Ball Super: Broly will hit Japanese theaters in December, and is expected to arrive in the U.S. around mid-January 2019. Dragon Ball Super is currently airing its English dub on Adult Swim during the Toonami programming block Saturday evenings at 9:30 p.m. ET. It is also available to stream on Funimation and Amazon Video. The Japanese language release of the series is complete and available to stream on Funimation, VRV and Crunchyroll.