The Powder Mage Trilogy by Brian McClellan, including Promise of Blood (23), The Crimson Campaign(24), and The Autumn Republic(25).
I am am heartbroken I didnt enjoy this series more. Promise of Blood was a brilliant book the first time around, and I reread it before going into the next two. On the second read, it felt a bit more shallow, though still a great book. Unfortunately, the sequels didn't hold up. Its still a good story, but the main characters are simply too powerful. They are given special powers, with no explanation, and to such a degree that other character comment on it. At first I though this was some kind of meta-commentary by the author, but since it never leads anywhere it leaves me feeling a bit confused.
Again, the first book is good, maybe even great. However it is actually cheapened by the sequels. They seem to rehash the same old ground every time, feeling very redundant. The books all open in very similar ways, the characters encounter functionally identical threats that all end in the same way. In works very well in book 1, but rehashing it twice more is just disappointing.
Before I picked these up, I thought there were only 3 books, but there are actually something like 6 now, all various forms of prequels set before and during the three main books. I'm actually still tempted to read them, with the hope that McClellan covers some new ground and actually goes deeper into worldbuilding.
And maybe that's the rub. There's this big world out there. He's got religion, politics, wars, gods, armies, command structures, gangs, police forces, worker's unions, monarchies, savages, a handful of different kids of diametrically opposed magics... There's just so much there to explore. So many ways the story could have been fleshed out. Instead, what you get is a couple of quick army campaigns with some flavor thrown in for interest, but I'm left wanting more.
Such potential left untapped, Brian McClellan has the potential of a great writer. I do encourage everyone to read Promise of Blood, despite the sequels, as it is by itself quite a fun read.