I have a suggestion for armour and weapon buffs that use other armour/weapons to improve your equipped items for a time. The length and amount of improvement depends on the class of item you use to buff it with.
So for example you have an exotic berserker sword that you buff with a rare carrion sword, the rare sword is destroyed but you get +power, conditional damage and vitality for the next 500 attacks or something. The higher rarity of the buff sacrifice the better proportion of stats it adds.
If its only available in PvE then its not going to upset the PvP balance, it will add another gold-sink for the economy and will allow yet more customisation of your character.
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