Ghostcrawler posted an update on the happenings regarding 4.0.1 balance, letting the community know that the previous buff to resilience was a bit much. They're going to be toning that back a bit, though resilience will still be stronger than when 4.0.1 went live.
He also mentioned that there are more class balance tweaks in the works, but wouldn't get into specifics. They're looking at alternative ways of implementing the previous buffs and nerfs, as the level 80 changes had adverse effects on players at level 85 in the Cataclysm beta.
We are going to take the resilience buff down a little.
It should end up as a 25% buff from where it stood originally, not a 50% buff. For point of comparison, maxing out resilience before our first hotfix reduced damage by ~50%. After out hotfix, the damage reduction with max resilience was 80%. With this most recent change, damage reduction with max resilience will go down to 60%.
Part of what is going on here is that we don't want newly leveled characters to explode in PvP, while still making sure that well-geared characters aren't invulnerable. The current resilience curve makes that a tricky thing to balance. Perhaps in the future resilience needs diminishing returns so that it doesn't keep getting better and better the more you have.
While we don't have any additional announcements to make at this time, there are some additional balance tweaks we're working on. Some of our adjustments at level 80 ended up causing certain classes to be overpowered or underpowered at level 85.