It's interesting that both this lens concern, and the antenna problems, may have been under-appreciated by Apple because much of their practical-use testing was with cases -- either in-house or for camouflage field-testing. Then, the iPhone4 ultimately launched without a broad variety of available cases, so most people used it without a case.
On my phone (Nokia N86), there's a sliding cover for the lens, which is a nice bit of reassurance. (It's also very convenient: open the cover, and the camera app starts up.) I wish some of the Android phones would imitate it.
For example I think the biggest problem with the iPhone4 was not attenagate but the material chosen for the camera lens.
After 3 weeks the phone camera is completely unusable due to blurriness from the act of setting it down on a table due to the lens being made of a non scratch resistant material and being flush with the casing that is.