One thing I find very disappointing is that they hint and tease at a whole plotline where you would actually join forces with the Absolutists and approach the story from their perspective, embracing the idea of being a 'True Soul'. They develop this storyline somewhat well in Act 1, and to some extent in Act 2 when you infiltrate Moonrise Towers. However, by that point, the game is already railroading you into the notion that you're merely pretending to be on their side. Eventually, this entire concept is dropped, and you're locked in as an enemy of the Absolute.
It would be amazing if that plotline were fleshed out and further developed until the end of the game. After capturing the Nightsong and decimating the resistance at Last Light Inn alongside Ketheric's forces, you could infiltrate Baldur's Gate as a True Soul to undermine the city's defenses, pursue your own agenda of overthrowing the chosen ones, or even undergo a change of heart, seek redemption, and become the savior of Baldur's Gate.
