"i wouldnt be surprised if people had multiple sets of armour so they dont have to keep repairing it."
That's funny! When I originally read the patch notes and Blizzard's official reasoning for the change, what you just said was one of the things that occurred to me.
One of the reasons Blizzard made the change was "to decrease inflation, particularly at higher levels". In other words, they wanted there to be more of a market for high-end stuff, particularly crafted goods. The question players have to ask themselves is, if they don't want to keep coming back to town, do they farm the instance to get the same armor/weapon/etc. drop they currently have, or do they get someone to make them something of roughly the same quality "just in case"? After all, is it really worth the trouble of instance farming for something you might not ever use? I think that's the sort of decision Blizzard is trying to get people to make. And if people just come back to the cities, well, Blizzard's been trying to encourage that, too. Blizzard wins.
Anyway, the system is still subject to revision and isn't even completely implemented yet. Remember, Blizzard explicitly mentioned that the way tradeskills interact with durability is NYI, so we'll just have to see how it turns out, won't we?