Also note that I do take the defense talent, which slightly increases the value of the defense stat.
Why would this be true? IIRC, the defense talent does not increase your defense rating by 2%, it gives a flat 2% bonus to your defense chance. This would mean that it has no affect on the diminished return on your defense rating, therefore not decreasing the value of the defense stat.
This same holds true for crit chance % increase talents, which is why I do not like it when people advise DPS to "get your crit to 30% unbuffed". Crit and defense stacking should be based off of ratings, not percentages.
Please correct me if I am wrong.