Ohai guys, I have an interesting idea of how to change it so that pvp gear is not worth it in pve. This is mostly aimed towards the weapon, obviously not the 4 piece bonus that's already fixed. (Although they could revert that change with this idea!)
Blizzard has stated many times that they do not want players to use pvp gear in pve. They say that players use the PvP weapons because they are superior to what they can get while not raiding. Same applies to the (current) 4 pc set.
My idea is simple, yet effective. Change resil to lower damage done against bosses. I'd say lower it by 5x the amount of damage reduction it gives. For example, if 200 resil gave 2% damage reduction, lower damage done by 10%. This will prevent players who only have the weapon (100-200 resil) from doing decent dps against bosses. Players can still do dailies or kill random mobs with no damage reduction, as this would only be effective toward bosses.
Keep in mind the percentage would be up to blizzard... Not myself. So what does the MMO champ community think of this idea? If you have feedback, please share. If you want to get your post count up, please go elsewhere.
edit - The damage reduction will be for instanced bosses. Not TB daily bosses. Possibly the instance in TB as well. Dunno, it's up to Blizzard how they want to do it.