Just finished A Way of Kings Part 1 by Brandon Sanderson last night. It's left me conflicted. For a start, it's only half the book, yet is 600.
It is a MASSIVE book. I gave some thought a year or so ago to how they could make a movie of it, and decided that it could best be broken up into two theatrical releases with a TV miniseries in the middle, and two animated short-story projects like the Animatrix.
I read it in a single hardcover, so I didn't face your angst, but I very much recommend you stick with it. I can't promise a resolution (after all, he intends this to be book one of twelve or some ludicrous thing), but there are some resolutions, some very shocking ones, and each characters story comes to some sort of personal climax, including some excellent battle scenes too. I came out of it with the same "damn this was long" opinion you had, but also "and it was totally worth it," afterwards going on to read Elantris and all the Mistborns.