Some update comments from Wow 3.0:
1. Crushing blows have been removed from bosses 3 levels above you - this means that shield block and holy shield are less important to have up at all possible times.
2. 490 defense is still important - just because crushing blows have been removed, bosses can still crit you! You still need to get to 490 defense as a priority (or 490 minus your resilience)
3. The threat mechanics have changed to favor Strength some more. While the gear list does not change, be on the lookout for any tank gear that has some strength on it as well. (There will be lots of this come Wrath time)