As someone who is not yet familiar with the Divinity universe (I played Divine Divinity, but it was a long time ago - I remember that I liekd it, but not more), my thoughts as someone without knowledge aboute the world:
The trailer gave me Wicker Man/Midsommar/ generell folk horror vibes and I'm in for it. Folk horror is one of my favourite genres, so I was excited. I do think, Larian is good with darker storylines - act 2 in BG3 was my favourite, I also liked the creepiness of teh Auntie Ethel storyline and House of Hope.
I loved the music a lot, it does fit the setting as far as I can say.
The whole setting looks pretty interesting to me and teh trailer made me curious.
In general, the Divinity titles trend towards more darker things than BG3 does.
With prominent themes of slavery, brainwashing, torture and megolomaniac mages that turn people into piles of goo on a whim (But by doing so cause eldritch horrors to seep into the world)
Honestly, it's to a point where if a Divinity game was to be portrayed with a more realistic artstyle... I could see the game receiving an AO rating and being banned in certain countries. Due to how dark and bloody it gets.
Like, a man being burned alive from the trailer is nothing compared to stuff like Kniles the Flenser, Shriekers and Eternals whom have to literally rip people's faces off to use them as a disguise...