I don't believe the new iphone issue is the same as the signal simply being blocked. I have a nexus one and will notice a drop in wifi signal strength if I hold it in landscape mode with my left hand over the top of the phone. That tells me the antenna is in the top and the signal is reduced traveling through my hand. It would be rather impossible to hold it the same for a call as your hand is over the speaker.

I iphone problem seems to be because the antennas are external and by touching both with your hand, you complete an electrical path between the two which disrupts reception. Seems like it would have been a simple fix to coat the antennas with something non metallic, treat the metal to make the surface non-conductive, or move them inside the case.