The simple answer is - different classes have different things. Perhaps they thought that being able to frequently dash fits pictomancer more than white mage. Some classes have mobility, some don't. Some dash, some teleport, some require a target or not, some have longer or shorter cooldowns, some do damage or not. Only the devs could tell you their reasonings why class X gets skill X with X cooldown - and I doubt they come into the forums and answer questions.