It remains to be seen whether or not software will FIX this particular problem. But at a bare minimum, software WILL be able to reduce the impact of the problem - and that may be enough to make it a non issue.
The entire signal process is digital, and is controlled by software. That software can be adjusted to match what is happening with the hardware. The iPhone 4 radio software is doing several new things which have not been done before. How and what they are doing will be tweaked as Apple learns more about the phone's real-world performance.
Will a software fix completely get rid of the problem? While that is possible, I seriously doubt that in this case software will completely solve the problem. But I do believe that software will mitigate the issue to where it is almost non-existent.
I wish this were true, but no, it really isn't.
"The entire signal process is digital, and is controlled by software."
Not quite. The signal transmission and reception circuitry is analog. At some point, the incoming signal is converted to digital, at which point software can manipulate it. But when the incoming (analog) signal is too weak, the digital values degrade in accuracy. At some low level of signal, the digital data cannot be corrected to the point where communication can be maintained no matter how you tweak the software.
This is true at both ends -- at the cell site and at the phone. If you degrade either receiver or either transmitter enough, communication will cease. And surely Apple has already optimized the software as much as they can.
While I acknowledge that it is
possible that a software change can help, I consider it highly unlikely. It is my opinion that it is the cell phone's
transmitter that is being most affected by touching the antenna. I surmise this from many years of experience with radio communications systems (which is what the cellular network is) in which I have observed that transmitters are generally much more affected by de-tuned antennas than are receivers.