My impression from BG3 EA that at best there will be two distinct paths player can follow - including it seems exclusive party members.
Than there is a lot of minor reactivity, which responds to what player did, but don't have much narrative weight or impact - so you can pickpocket a key item, and than see how the character will react if he reaches the point in the script where he is suppose to hand you this item. Stuff like that.
It is difficult how far reaching consequences will some minor action have - I suspect who lives and who dies will be the main difference between playthroughs.
