I'm just at the begining of the game and while the gameworld and the lore are marvelous the plot is terrible. It is supposedly a tale about revenge, but we have no real motivation to avenge the murdered, because we just saw her for the first time a minute before that happened. The 'kidnapped child' hook feels just incredibly hollow. The reliance on briefings and infodumps makes it feel like Corvo is just following orders and shows little initiative on his own, which doesn't help getting involved in the story. You are just told 'you will work for us and assasinate people we tell you to' and have no choice but to accept. Also how the magical powers are introduced - some guy explains you how it works for five minutes.
Contrast this with the game's inspirations, Thief and Deus Ex. In those games the story evolves gradually, villains and allies are introduce and secrets pile up. Both of these games use the 'you are betrayed and left for dead!' idea, but that happens after a few missions not in the intro, so the player actually gets to experience a sense of loss and broken trust. At the start of Thief Garret is just operating his business as a master burglar, he gets dragged into issues greater then himself, screwed over by his employer and then reluctantly has to save the city. Dishonoured could have followed a similar progression, with Corvo working as the bodyguard and servant of the Empress for the first few missions around the city of Dunwall, getting to know the realities of the place, perhaps helping her majesty to find a cure for the plague and only then would the assasination twist happen. Instead the game just lays the cards on the table, unless there is some enormous twist coming that's somewhat disappointing, given the overall quality of the worldmaking, the visual imagery and gameplay I've seen thus far.