I am new to adventure paths, so I have little to compare this player's guide with. That said, I have played D&D for over 30 years and used a lot of product.
The Wrath of the Righteous makes no bones about being a campaign for Good Aligned Characters. It is very up front about this, and warns that evil characters will have a hard time fitting in, and that campaign information will not provide support for this. Fair enough, nuff said.
The traits are perhaps limited in number, although as an ideally diverse party, this was not a problem for us. It should not be a problem for several people to choose the same trait - in fact it would provide a useful connection between characters if they do. In a perfect world, there could have been a couple of traits designed to fit each character type, to allow some to feel a little more creative freedom.
The information about demons sidebar is a wonderful snippet - it gives characters just the right amount of "in game vs. meta-game" knowledge about demons that a character living in Kenabres would likely have. It is also good that several famous villains are enumerated - it makes you feel that much more motivated when you hear the rumour that the demon-witch Areelu Vorlesh is coming!
The only "missing" for me is some organization information - organizations that might exist in Kenabres and surroundings to further tie characters to the campaign, or give plot hooks. Admittedly this might be beyond the scope of a Player's Guide - but I would have appreciated it all the same.