Originally Posted by Warlords of Draenor Patch Notes
Hit and Expertise were not fun stats. They acted to remove a penalty, instead of making you stronger. Most players treated Hit/Expertise caps as mandatory (rightfully so), with failure to reach those caps as a trap of sorts. After adjusting, gemming, and reforging gear to meet that cap, players could then go after the actual damage-increasing stats. We decided to remove Hit and Expertise, and make it so you don't need them. We still want melee specializations to attack creatures from behind when possible, so attacks from the front will have a 3% chance to be parried that cannot be eliminated for non-tanking specializations.