If your only consolation to DR to begin with was the more linear effect of increased avoidance then I can see why this would be described as "devaluing dodge." It is true that without the 20 percent reduction getting enough dodge rating to give you one additional percent when at 30 percent dodge meant a bigger number of your previously undodged attacks were now dodged (1/70) then it will under the effects of the 20 percent reduction (1/90). This means that the effective avoidance increases under dr will not have that neat linear look that has been discussed in detail in another topic post. It does not however devalue dodge relative to other avoidance. A point of doge rating will still be worth as much with the 20 percent reduction compared to a point of parry as it was before, and the fact that dodge diminishes towards a much higher number means it will still be the more efficient place to stack avoidance.