The Fires of Heaven is mostly a book to extend what we’ve seen before.
Elida solidifies her control on the tower while the rebels come together to oppose her. Nynaeve tugs her braid. A lot. Elayne and Nynaeve end up in the circus (not even kidding) and with a captured Forsaken...
Egwene continues her studies with the Wise Ones, growing stronger in her control of Tel’aran’rhiod.
Mat begins to learn just what he can do with the memories in his head… and Rand finds that he will use anyone, even his friends.
Perrin… isn’t even in the book at all. I guess he’s off doing honeymoon things with Faile. (I honestly didn’t notice until I couldn’t remember what he did and looked it up…)
All together, it feels like the weakest book thus far. But that’s mostly because you can’t keep up a pace like that forever. Eventually you have to dig in and really build the world, which is what we’re seeing now. It’s still well worth the read and hard to put down.
One interesting note: This is one of the first big cases we see of just what balefire can do. Reversing the death of a whole pile of main characters? Oy. That's quite a thing. It hits less hard than it did the first time, since I know they'll all be in future books, but it's still an intense scene.