While thinking at the huge problem blizzard has with the fact items lose their value day after day until they are worth zero due to the proliferation of items.
In diablo 2 (yes, I know, but keep reading), there was many utilities of using ethereal (can't be repaired) items even if you could not repair them resulting in the lost of the said item.
They had higher damage if it was a weapon and more defense if it was an armor (50% more if I recall). Their stats could be boosted in D3, anything to make them valuable.
In PVP it could made a huge difference (50% boost is a lot). The downside was that you constantly had to buy these items. I think it was possible to repair them with rune but it cost a lot to do it if I remember. Every time you needed one rune to repair it and the rune was consumed. D2 players had to repair it every games or so of PVP.
This is an interesting concept that could be implemented in D3 to keep the economy rolling and thus blizzard gold sink working. With a consumable people DEPENDS on, you force them to constantly spend to repair their godly items.
You would also need these items (screw the account bound items, we are not in WoW) to beat the end game content (with a reward like more ethereal items - these items are very good but ethereal and cannot be repaired by anything - not even by a consumable [that's simply an idea among many]).