BG1 was very open, but BG2 wasn’t. You could only travel directly to locations outside of Athkatla after you learned about them from NPCs, as opposed to just picking a direction and going on a journey map by map like in BG1. The OP admits this, so it makes it a weird thing to critique. Would it be nice if BG3 was a giant open world, sure, but I’d rather get the game in one year instead of three, and at a certain point Larian will start seeing diminishing returns in how much they are invested versus how many units they will sell, so it just isn’t happening and really isn’t worth talking about.
