For I've read, SE nerfed the Stoneskin on WHM from 18% to 'normal' 10%, because in ARR they numbers where low and since we're getting better equipment and higher HP... They decided that 18% is too much. That's why they nerfed. But, I remember the old days of ARR where I used to join as SCH in Dugeons and whenever I used Stoneskin on tank, the WHM would do it just right after me, like saying 'yours is awful, leave it to me'. Same was valid to Protect, where WM's Protect would give both Physical and Magic protection awhile the SCH/PLD would only give Physical protection. Oh.. good old times...