It was announced today that there will be a major change to resilience, which is being hotfixed into the game as we approach the new arena season. The change is expected to be in place for the duration of the Wrath of the Lich King expansion; which we take to mean it will not carry over into Cataclysm.
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.