As I expected the trailer didn't tell me anything useful or meaningful. It's a movie trailer, which makes sense as BG3 is more a movie than a video game. Just lots of pointless cinematic fluff.
I think you're being a bit harsh on the trailer. For starters, it's still about 10 months away. It also explained the basic story-face the cult of the absolute and deal with the tadpole in our brain. For anyone not in early access, that's I think the first solid reveal of those aspects of the story. It did show some bits of gameplay as well. Its not for us in early access, it's for people who either weren't aware of the game or were aware but not following it/not in EA.They've also got a major, mechanics-focused event coming next week. That'll go for an hour or more. This trailer is about building hype for sure, but what more did you expect from it? If there weren't a panel from hell on the way, I'd be more critical too.
