It was already announced over the weekend that Ultra Instinct Goku and Kefla have both been added to the Dragon Ball FighterZ character roster. However, three more characters are yet to be announced this season, and while there is no confirmation, Omega Shenron could be one of them.
Omega Shenron is a character from Dragon Ball GT, the most powerful of the show's final criminal group, the Shadow Dragons, evil creatures born from the negative energy stored by the Dragon Balls who then rose to try to destroy the world.
While the leaked audio in question doesn't refer specifically to Omega Shenron, the line was originally told to Omega Shenron during Gogeta's fight with him in Dragon Ball GT. It could be a general taunt, but it could also be one tailored to be used on Omega Shenron.
Dragon Ball GT was essentially declared non-canon after the start of Dragon Ball Super, but since Gogeta made his first GT appearance, some fans may be extrapolating that more GT content is on the way. However, without context, who knows who the next Dragon Ball FighterZ character is.
There is a large number of other Dragon Ball characters that could be chosen just as easily, including various characters from the Tournament of Power, who could fill those three slots, although obvious predictions like Jiren have already been released. However, we won't know exactly which characters are filling up the remaining slots until they are actually announced.
Who the next Dragon Ball FighterZ character will be is likely to be in several weeks or months and whether Omega Shenron will still be the subject of debate. But hopefully, whatever the character, they will be great.