Beyond the basic paladin tree changes and gear announcements, I honestly haven't looked much into the 2.3 nuances because I have been busy (and "busy with my on-and-off love affair with Steam :P). Patch 2.3, which has a confirmed release date for November 13th, is introducing Weapon Expertise, a combat mechanic which will be replacing Weapon Skill.
Expertise Rating has the same conversion rate as Weapon Skill: 3.9 Expertise Rating to 1 point of Expertise Skill at level 70. Many of the other affected mechanics also remain the same unless I am mistaken (probably am).
- Each point in Expertise Skill also reduces your target's chance to dodge and parry your attacks by 0.25%
- Expertise isn't limited to one particular weapon (unlike Weapon Skill).
- Every level a mob has over you, its dodge and parry will increase by 0.2%
The expertise cap
In other words: how much Weapon Expertise you need in order to become immune against a boss mob's parry and dodge. From a tank perspective, having all of your melee attacks land means more threat generation. Recall that at an equal level, a mob has a base 5% dodge and parry. So a level 73 mob would have a 5.6% dodge and parry (3*0.2 + 5). At 22.4 Expertise Skill and 88.36 Expertise Rating, your attacks can never be dodged or parried.
What about the attack hit table?
To my knowledge, the uncrushability calculations remain the same, but I am not 100% sure since I haven't looked into the new changes in depth. I need to update the guide since Weapon Skill was nixed.