Siege and Storm is better than Shadow and Bone for one reason: Nikolai Lantsov and Sturmhond. There is a lot less of Alina and the Darkling, although both do appear, and that’s not a bad thing. That part of the story shouldn’t really be the focus anyways, given how much Alina keeps focusing on one objective, first learn how to Grisha, then get away from Darkling while trying to find the sea snake/ice dragon and then fire-bird (and that quest is barely even mentioned)/maybe become some sort of queen. At least Mal has one focus, even if the only apparent reason for it is childhood loyalty. As much as Mal is kind of a non-presence, at least he has a sense of what’s going on with him Alina, while she can’t figure out or articulate it. Again, they are supposed to be teenagers, and Alina is definitely acting like one, but with everyone else around he age being more together than she is, her total inability to read the room in most cases gets irritating.
Nikolai on the other hand has a firm idea of who he is, what he wants, and has the flexibility to change gears when necessary. He’s also got more personality than Mal and Alina put together; we could even add the Darkling with his brief appearances and still Nikolai is more interesting. That’s one thing Alina at least does get right, namely her observation that he’s actually pretty focused on one thing, the welfare of his country even though there’s a chance he’s not technically the son of the king.
The dream stuff is kind of a waste of space since it doesn’t add much of anything to Alina or her story, and the final confrontation between her and the Darkling (which clearly is not the end of things given how it ends and the fact that this is actually part 2 of a trilogy) is kind of dumb. Given how hopeless she is for the entire novel, how does she suddenly gain control? The shift in power, both hers and the balance between the two, has no real explanation, and how things stand in the end is no different than how they started: poor downtrodden Alina, but somehow she’ll get the power/situation under control and win?? I’ll finish the trilogy, but not for anyone other than Nikolai and just to be done with Alina and the Darkling; it’s obvious how this is going to turn out, just not quite as much in how they get there.