Of course, when you're trying to wrap up ~1,000 pages of non-stop action involving dozens of characters & roughly 700 years of history, there's probably just no way to do it that is going to 100% please everyone. Like he says in the epilogue, there's a certain point in writing a long, complex series with lots of characters where it suddenly hits you that you made this mess, & now, somehow, you've got to clean it all up. I think the conclusion was well-written, though, & there was a lot of integrity about the way it played out for each individual character, & that alone makes it better than like 80% of the long-form fantasy I've read.
My only real complaint is that at ~1,100 pages, it's a bit short for an epic fantasy trilogy. In the epilogue Weeks talks about mercilessly slashing sections from all three books in order to make the story tighter and stronger (which clearly worked--there is not an ounce of fat anywhere on this baby), but because they're all such great and well-written characters, I actually would have been interested to delve a little more deeply into some of the supporting characters' side plots/back stories. (The edition I had included two such bonus chapters that he admitted he regretted cutting, and I thought they were lovely and would not have slowed the main narrative at all.)
In short: This is a great trilogy and Weeks is an amazing writer. If action-packed fantasy with really well-written characters (particularly kick-ass women) is your bag, don't miss it.