I thought the Anandtech article explained it pretty well and put out some fairly damning evidence that the grip we use causes 2x-3x the attenuation as it does on other phones. I'd like to see them do the right thing and at least offer a free bumper to customers... even if they won't come out and admit the phone's faults.
The 'problem' is that the same article pointed out how it was still able to make calls in deadspots that stumped the 3G/3Gs, making it easier (though no less lame) for Apple to just ignore the issue.
Oh well, I am just happy I don't cover the antenna when I hold the phone, and when I have, my connection has not been degraded (at least my calls have not dropped or my data stopped transferring). In fact, I can make calls from deadspots out in the boonies that were a no-go for my 3G.