People soon got over that when a back could be replaced for about $20.If I remember right, didn't people complain that the iPhone 4 was made of glass when it was released? Wasn't the complaint that it could crack or break too easily? It's funny how this works.
How much do you think it's going to cost to completely strip down an iPhone 5's back so you can replace it? The back is the phone.
As far as accidentally bending the iPhone 5, I figured out how fragile it was (compared to the 4/4S) after holding it for about 10 seconds in the store. If someone bought a 5, they damn well should know how fragile it is compared to the the 4/4S and have no excuse for 'accidentally' bending it.
It's like: Oh, my, this very very thin and very light and very tall/skinny phone bent in my pocket when I hit a table or sat down..." That one's on you. Me, I just didn't buy the damn thing.