I don't mind a bit of math if it's hidden. It doesn't have to be announced anywhere, just state in the manual that "As a item's durability decreases, it becomes less effective." The Durability text can change from white to yellow to red to signify this.
I always get bugged when they give you numbers that make no obvious sense, like Offence, Defence and Armour. What the hell do they mean? There's no obvious maths behind any of them except that higher is better. Diablo had the worst description of Offence. I had a 125% Chance to Hit, yet missed two-thirds of the time because of their Armour.
