Similar to how Tier 0 and Tier 0.5 are all ready available, make T1-3 available to use for all classes as long as they can use the armor type (cloth, leather etc.). I think this would be an interesting addition, allowing for more in depth customization for all classes and specs without adding completely custom gear to the server. These can be added to the current Tier vendors and prices should remain the same, and the only way to obtain cross class Tier gear would be with gold.