as per the PTR Notes.
All permanent item enhancements provided by Enchanting, Engineering, Leatherworking, Tailoring, and various vendors and quests are now able to be applied to items of any level. This means all enchantments can now be applied to heirloom items.
High level enhancements applied to items equipped by low level players have their power scaled down to be similar to enhancements intended for that level range.
Low level enhancements applied to items equipped by high level players do not grow further in power beyond their intended level range.
So really I'm wondering. Has anyone started working out what the best enchants will be?