This change will "double the value of resilience in reducing damage done by players," according to Bornakk. Players will see a 10% to 20% reduction in damage taken. However, this change will not affect critical strike chances or critical strike damage. If healing becomes too over powered with this change, Blizzard has a "PvP only solution" ready to go, however they're not rolling out that part of the changes just yet.
The full details after the break.
We are currently in the process of applying a hotfix to buff resilience. While some modifications may be made, we intend to have this buff in effect for the remainder of the Wrath of the Lich King expansion.
The change will double the value of resilience in reducing damage done by players. So depending on their current amount of resilience, characters might experience a 10 to 20% decrease in damage taken from other players. The critical strike chance and critical strike damage reduction components of resilience will remain unaffected by this change.
We are also aware of the possibility that this change will make healing in PvP too difficult to counter. While we are not making any immediate changes to address this issue, we have prepared some further changes that will allow us to quickly deploy a PvP-only healing adjustment if we feel it is warranted.
We will be applying this change very soon while we are between Arena seasons so we can evaluate how it works in multiple PvP scenarios for the upcoming Arena season, and as we continue to prepare for Cataclysm. As we have mentioned previously, one of the goals for Cataclysm is to have a PvP environment where it is harder to regularly achieve so much damage and healing in relatively few global cooldowns compared to what we currently have in the game.