I also just think that the antagonists are the wrong characters to use for the marketting in general. Because these three antagonists don't have a meaningful presence in act one, we're not going to be building a relationship with them, and I think honestly that with how the game is constructed, we're just not gonna be building an emotional bond to them as players or as characters. They're going to obstacles to be overcome more than anything else. I think it would have been better therefore to focus on the companions we've not yet met. There's less chance of spoiling story beats later into the game and they're the characters we as player and PC are going to be building an emotional attatchment to and, in the case of the Origin Companions, playing as. Hell, it would be a great opportunity to properly introduce and explain Jaheira and Minsc to newcomers to the franchise. Brief trailers like this that can contextualise who they are and why we should be excited about them. Because as someone who only just dipped their toe into BG1, I know enough to know they're important, but I don't really know WHY beyond 'they were old, well-loved companions.'
While I can respect this opinion, I feel somewhat differently.
Take Saravok from BG1. He, or at least the voice actor who played him, appeared prominently in the promotional material prior to release. And David Warner (who voiced Irenicus) was not only ubiquitous with BG2, but was the very first character you see in game. And both games sold well enough for a third game to be made.
If you want another example of this, take a look at Kang in the current MCU. He has been marketed as 'The Big Bad' of phase 5 for quite a while, with his first appearance in the Loki series. He is the main antagonist of Quantummania, and will have his own Avengers movie. In Antman, he doesn't appear proper until act 3, yet he is absolutely important to the promotion of the movie. And even his role in Antman is merely a prelude to his Avengers debut. And unless I am mistaken, Thanos was foreshadowed quite early in Phase 1, yet didn't actually appear in any real context until Guardians.
While there are differences between movies and video games, marketing for these two media types is often very similar. It works in most cases, and I believe it works here. Yes, we know a name and a face for one of the baddies. But we don't know actually know, at least I didn't get, from the trailer if he is going to be the ultimate baddie (Saravok or Irenicus). Simply that he is in the mix. We still have 2 chapters for that relationship to play out and I for one am quite thrilled to see how it unfolds.