I have been reading, some of the posts, but I do not see any mention to this.
I believe one of the best upgrades is the the addition of the sapphire lens. If you own a high end watch you know what I mean. The material is almost scratch resistant.
I enjoy taking pictures and videos with my I phone 4, but after 2 years, the lens has some scratches. Not sure about the optical characteristics, but I welcome a "scratch resistant lens"
I have a TAG Heuer which has Sapphire Crystal face but for some reason that has scratched! i suppose it depends what grade is being used! but yes it will defo be more scratch resistant that those in the current model!