Please, the cleric book was the gimpiest of the series, it actualy suggested nerf the PHB cleric to help the option therein look less worthless.
But at least the Priest Handbook allowed you to create characters who were far cooler the the generic cleric, and could be strong in their area of specialization even if they were weaker overall.
I have to agree with Felon that the Thief handbook added very little to the class compared to the other splats, probably because it was focused on simulating real life thief equipment while the Ranger handbook was teaching players how to turn into a tri-wielding tree man.
Aside from the Swashbuckler of course, which is still one of the most laughably designed kits ever.