Some items have scores that are far too close to each other considering how much better one is than the other. the belt of blasting, for example, is only 3 points higher than the belt of divine inspiration, a belt that is no where near a good. perhaps instead of assigning a score to each item, change how much each stat adds to your score depending on the class and perhaps give two scores, a pve and a pvp score. That way, a raiding lock would have a low pvp score and high pve score, and a mage would have different scores.
Or, you can give scores not based on each item, but scores based on your stats in general... such as how much +dmg, hit, and crit you have unbuffed. or even a combination of both.