For certain armor you have to have the right amount of points invested in a skill tree. So a pure mage just cant throw on some bad ass heavy plate armor. But if you are going for the jack of all trade destinies, I think the Universalists Destiny lowers those requirements.
It's not just the Universalists Destiny that lowers those requirements, it's every Jack of all Trade destinies. It cuts the equip requirement by half. Weapon requirements are level based, while armor is ability based.