My suggestions:
Take away Kazmojen's proficiency with his urgrosh and have him stick to his claws - with the urgrosh, he'll slaughter your party, taking down most PC's in a hit or two, and he's got two. Without it, he's more of an interesting challenge. I'd replace his urgrosh feats with something else.
Try to have the bad guys gang up on the PC's. The first level of the dungeon is filled with encounters consisting of a single skulk, or a pair, and they tend to go down to a single hit. If you have them act a little more dynamically, larger fights can turn out to be more fun.