Actually, that's not as off topic as you might think, it outlines an issue that is currently being had with Ranged combat, one that has been addressed to staff already in a post that is SOLELY for changes to PvP. However, the 15% is slightly too high in my opinion, instead of changing it to 7% reduction, perhaps change it to 10%? This way, they maintain their ability to soak up damage, but not be invincible when they get attacked.
With that being said,
Aira1, if you haven't done so, add this to the "Changes to PvP thread" (I believe that's the name anyways... It was posted by Thortuna a while back) once you are satisfied with all of the aspects of this idea. Right now, it seems like you want them nerfed, but you're not certain how much they should be nerfed by. I agree that they should be nerfed, but possibly only by 5% so that they can still maintain their rank as a viable tanking class, that being said, perhaps another "tanky" class could be implemented to help with this? I don't play undead because in my opinion (and as stated in the lore) undead is an "evil" race, I would rather not be considered evil, but in order to get a defensive bonus, I'd be forced to as it currently stands. So, my idea for this would be nerf undead by 5% and then possibly add another race that would be able to tank as well, preferably a race that's considered "good".