After hinting at it for a few weeks now, Blizzard has finally announced changes to the way resilience works. The hotfix will potentially have a huge impact on arenas, doubling the amount of damage reduction. Critical strikes, however, will still be reduced by the same amount as before.

Aware that this might make healing too strong had this to say: "we have prepared some further changes that will allow us to quickly deploy a PvP-only healing adjustment if we feel it is warranted." The changes are meant to be a kind of stop-gap measure until Cataclysm launches (date TBA). Blizzard estimates that an average player will take around 20% less damage, depending on their resilience.

Although the change appears somewhat radical, Blizzard is taking the important step of adding the fix between seasons. This should give them time to judge the affect it has on the game before the start of season eight.

In a related post, Ghostcrawler gave a little more depth to the subject. "I think teams may try to focus on PvE gear as a way of blowing up healers on the other team," he said. "If that doesn't work [...] the PvE-geared guys won't have the survivability to stick around long." Again, though, he was wary of healers becoming too dominant. "If you can never defeat healers (note I said defeat, not blow up in 2 globals) then we will need to nerf healing."

The blue poster went on to underline the fact that the changes are designed to make games a little longer but not too long: "20 min matches can be as tedious as 20 sec matches are unsatisfying."

Source: World of Raids