I'm not sure if Banner Saga is your best point of comparison here. I'd say that both PoE and Banner Saga suffer from a similar problem, in that both are set in interesting, well-developed worlds with some intriguing twists in their lore, but at the same time both narratives suffer from serious pacing problems.
Without getting too far into spoiler territory, Banner Saga in particular sets up a number of important plot points that are never resolved, as well as introducing a significant villain whose role is neither fully addressed nor explained. A common complaint among people who finished the game was that the ending seemed to come out of nowhere, with a number of major plot threads still left dangling. Granted it's planned as the first in a series, but a narrative which results in such common surprise among players can be fairly blamed on serious pacing issues.
I didn't notice any pacing issues in Banner Saga - in fact one thing it does really well was the consistency of pace. You are constantly pursued, on the run, until towards the end when you find you are being slowly cornered, then you end up with nowhere to go, and must make a last stand.
It really makes no sense to expect closure on plot points in a game that was announced as a three parter. What made sense was to expect closure to the first arc, which was done quite satisfactorily. The other plot aspects, the disappearance of the gods, the serpent, the stopping of the sun, the darkness driving the dredge south, were actually quite obviously going to be left for the sequels to answer - realistically only someone with a very low level of common sense would have actually been disappointed at the lack of answers to those.
Banner Saga also suffered from a bit clunky, weak characterization. None of it is outright bad, but after finishing the game a couple months ago I struggle to describe in any detail important plot players, what their characters were like, what motivated and what troubled them. I can already tell that in a few months time Pallegina is going to fade into nothingness and Kana I'll vaguely recall as the loud bard guy, but Durance, Grieving Mother and to a lesser extent Eder are probably going to stick. They were interesting, and that's to PoE's credit.
I actually thought that considering you are given about as many NPCs as BG1, they're fairly well fleshed out and memorable. You have Rook who is trying to save his people, Ludin the arrogant prince, Onef the traitorous pragmatist from Frostvellr, Ubin the scribe, Yrsa the witch, the drunkard Sigbjorn. They're quite interesting, and several play key roles in the plot or party. It's not really a fair comparison to POE's much more limited character pool. Pillars of Eternity has only one more character than Planescape Torment, it really should have been able to hit that level of depth. The fact that by widespread consensus, POE only managed to make three out of 8 characters relevant or memorable really just illustrates what a failure the game was.
I really brought up Banner Saga to illustrate how much more thought went into the setting and overall lore, but really, considering that those characters basically play the role of chess pieces, many of them were developed in much more significant ways than they needed to be. Others like Hogun and Mogun of course are just there to kick ass and shred enemies to bits (apparently they are really impulsive, and there are several scenarios in which they can abandon your party or get killed, but I didn't experience that in my playthrough).
My point isn't to harp on Banner Saga - I agree with you that it's a great game made with serious heart, and apart from some stern reservations over the final boss fight I'd heartily recommend it to just about anybody - but rather to point out that both games require the player to dig a little bit to get what's good about them. PoE buries its virtues so far beneath clunky exposition and questionable design that I can't really begrudge anyone for not wanting to unearth them, but I don't think it's quite fair to hold Banner Saga up as a model of doing right what PoE does wrong.
If a person is put off by Banner Saga's exposition I can't really blame them, since it's the job of the game to engage you. Pillars suffers from the same problem, probably to a much greater degree. At the same time, though, it seems myopic to me to pretend that games like Banner Saga and Xulima are great games in spite of their flaws, and then pretend that Pillars is without meaningful redeeming features of its own.
(very briefly, in case someone is thinking to ask what I think those meaningful redeeming features are - some memorable, well-developed characters, some well developed areas with the castle assault in particular standing out, enough combat options to keep me at least entertained through a single playthrough, some intriguing concepts unfolding in the core narrative ... of course a lot of these are offset by plenty of criticisms that I think are very much on point, but at the end of the day all I can tell you is that I'm fond of messy ambition ...just wish it didn't have to be so suffocatingly grim)
Unfortunately those supposedly redeeming features are really like shriveled trees in the middle of a desert. The game just has too much bad and mediocre.
(tho' it's true that the IWDs had a bit more exceptions to the rule, so there's that in Sawyer's defense I suppose).
