I have exactly the same problem with it that I had with the first book, and it's this. I want to like it more than I actually do. Sure, this is the reviewers way of saying "It's not you, its me", but quite genuinely there is a large amount of stuff in this book I really like the idea of, but it never really gels for me. First off we have the protagonists, Locke and Jean, going by a wide array of alibis as the story progresses. If "old-school" fantasy relied on power-fantasy characters based on a presumably geeky outsider reader being able to fantasize about being bigger and stronger than everyone else, then Locke is the same urge except being smarter than everyone else.
Locke is written to be an enigma - he keeps eluding to the fact its not his real name, for example, and I find him really un-engaging because really, there is nothing in him to hang onto. His motivation in the whole book is at first, to go to a place and get a big score, pretty much just for laughs, and later to be free of someone who managed to get one over him, without any sense of wider motivation or duty. I mean, what does he want? Because as far as I can tell, proving he's smarter than everyone else seems to be it - it's a teenagers motivation and thats all very well but I'm 20 years gone from empathizing with that.
This isn't a cry for any sort of morality tale, I hasten to add. But worlds of Black and Grey morality still need character motivations to latch onto, to make you care, to engage you in the story. The Archon may be an asshole, but he's an asshole with ambition, a coherent set of desires and the capacity the express what he wants to do. Locke wanting to escape the net is a fair motivation, but given he's only in town to rip someone he'd never met before off, no reason other than that "it was there", it's hard to feel anything about being ensnared in the first place
This isn't to say this is a bad book - the second half, when the promised Pirate-y action finally arrives, cracks along, the supporting cast lights up and the whole thing is a hell of a lot more fun. Not totally convinced about the (spoiler) grim death of of one of the main characters love interest, which feels like closing off a more interesting change in the series dynamic in favour of a return to a "status quo" ending. But by and large when its on actual seas (Red or otherwise) I found myself relaxing into the book and its characters. The finale, of course, relies on going to the earlier themes I was less enamoured by.
Gosh reading back this feels really harsh. Overall, I mostly enjoyed Red Seas under Red Skies, I just don't think I enjoyed it as much I expected to. If you read me a synopsis I'd be right there with it - Heists, Pirates, Adventure! - but somehow it just doesn't click for me because when it comes to the stars of the book, I really find it hard to care.