You know, we like to blame Apple and Steve for the problem with the iPhone...but tbh, the FCC and AT&T figure into this equation as well. The FCC regulates that the antenna cannot be too close to the brain, so the antenna is located at the bottom of the phone near the mouth piece, which is unfortunately where folks are going to be placing their hands.
Since the antenna is part of the exposed metal frame, this means that when a hand is placed in the right way, the signal is interrupted by someone grounding out the antenna. Hence, the bumper goes a long way to eliminate this problem. So if you have an iPhone 4 and are worried about reception issues, get a bumper.
As to the software update, I am willing to wait to see what Apple has to deliver. My history with them has been very good with regards to delivering fixes to known issues I have experienced directly with their hardware/software.