Day and night cycle. That's what he's referreing to. 100%. No way it's not about it.
I know there’s a good chance you weren’t being serious, but for context here’s why this type of reveal is unlikely: ask yourself “Why in the hell would they need to keep it secret if that was a feature they were adding to the game?”. This would be advertised to hell and back as a feature.
I’m afraid that the people suspecting some “meme stuff” are a lot more close to nailing what Swen would promote as a big, exciting surprise.
Party control in Baldur's Gate 3 is a complete mess that begs to be addressed. SAY NO TO THE TOILET CHAIN