I didn't mean specifically that particular armor. We get enough "bonus" stats from full/partial matching armor sets already. But something like the magic symbols. Maybe create some weaker/stronger craftable set which requires items from across your world. This would ensure that for creation of such an item - professions products, hunting drops/quest resources as well as valor, would all be needed.
This could be a relic armor like for example a Blessed Boobplate of Sheara. Wearing it alone, it gives regular purple armor bonuses. But when you combine it with the Unholy Garter of Sheara, it gives certain bonuses like Per-Flar Symbols, or Life leech, or even chance of a similar to Dragon/Aladeya blessings.
Could also give race specific bonuses like chance to summon a Wraith, or a card monster/Card effect.