Eh, he's getting the criticism because the book just isn't very good. The other two books in the series have managed to tell their own story while contributing to the narrative; his just wandered, setting lots of stuff out there without doing much with them. And oddly (to this point), all the stuff he set up or left dangling, the other books in the series didn't pick back up, so it feels even stranger and more disconnected.
Lots of time wasted with flashbacks.
Kira stuff was lengthy, but no apparent payoff so far
Surprise ending wasn't even mentioned in the other books
Mostly, just no feeling that it was building to anything. Not a story in it's own right, just the first couple acts of a story. No payoff, no climax/conclusion, it just sorta WAS. If you can't resolve the big story (obviously not in an opening book), gotta introduce smaller things you can deal with. Didn't happen.
Aside from the Kira stuff being weird, it wasn't BAD, it just wasn't good. Without a conclusion, really wasn't much of anything...
As-is, it could have been the first 3 chapters of Crimson Shadow and we wouldn't have missed anything. President gets killed in opening of book 2, did you lose anything? That's really the knock; it wasn't necessary. Nothing would have been missed if book 2 spent a couple minutes telling you what you needed to know, or if all 4 books had been a couple pages longer...