Could you make it so that when calling fetchItem it will fetch the character specific item if the character is set in the class?
For example... The item "Willow Belt" shown on WoWHead as ItemID: 6539 has no particular properties if fetched from the armory currently... however if you specify realm and character when calling itemtooltip.xml it will fetch the version of that item being worn by that character on that realm
Try it out with the item mentioned above on US realm "Hyjal" and character "Chaney" to see what I mean.
This method will also cause the tooltip to include enchantments on that item as well.
It might need a little reworking in the parsing method to account for random properties etc all having the same "<enchant>" tag and so at present it will only show the last one.
Hope this helps you improve the class :)