CotAB: Guidance
Not all of the content in Curse of the Azure Bonds is related to the main quest. Pretty much every town on the map has a dungeon of some sort attached to it, as if the presence of ancient ruins or natural cave systems is some kind of prerequisite for settlement. These little dungeons are like a regularized form of optional side-quest. And it’s kind of strange how that feels.
I am of course comparing it in my mind to Pool of Radiance. PoR was composed mainly of optional quests, but there wasn’t a great distinction drawn between side-quests and the main quest line — if indeed you can even claim that there was a main quest line beyond the general effort to gain enough experience levels to stand a chance of beating the end boss. The whole thing was an undifferentiated soup of missions, and the assignment of those missions was more like suggestions than orders; you could generally collect the reward for doing obviously beneficial things for the colonists, even if they hadn’t been requested yet.
In contrast, CotAB, with its five separate sub-quests, makes it clear when you’re making progress in the plot. Which means that I’m acutely aware that I’m not making progress when I explore a cave just because it’s there. It has to make the distinction clear, because it doesn’t provide a lot of external guidance about where to go or what to do. The closest thing it has to the PoR‘s council clerk is a mysterious cloaked figure who you meet by a historically-important standing stone. He’s probably Elminster. I have only a vague notion of who Elminster is, but he’s mentioned a few times in the docs, so he must show up in some capacity, and this is the closest thing a Gandalf-like adviser I’ve seen so far. But he doesn’t advise very much; he basically just tells you “Seek your next adversary in the northwest” or whatever.
Without Probably-Elminster’s vague advice, there would be no obvious reason to pursue one major sub-quest over another. It seems likely that he puts you through things in optimal order — that is, from lowest-level to highest, matching your characters’ advancement — but I’m not entirely sure that’s the case. For one thing, he’s kind of out-of-the-way. Nothing guides you to him from your starting location, and if I had chosen to go around the north edge of the world map first instead of the south, I wouldn’t have met him until after I had been through the second or third of his advised route, and you’d think the designers would have planned for that. Also, the first place he told me to go seemed a lot harder than the second. But perhaps that’s just because I hadn’t yet got a lot of extra experience points from optional side-quests.