What I think eBay should do is to make it a little harder to leave negative feedback. Maybe a process similar as the one they have to report NPB's. Or maybe a 2-step process, whereby the negative feedback is left, but the poster has to wait 24 or 48 hours to confirm it before it's published. That could give the other party a chance to do something to solve the problem, or allow the poster to cool off -- maybe the poster had a bad day and the cat was hiding (no one to kick).
We have had only one neg (which the buyer retracted). It was left by the son of the registered member, who purchased an internal PC CDRW and could not find a power cable. The manual said "connect the power cable to the drive," which meant to connect that internal power cable in the PC to the drive, but the kid thought there was a cable missing. We phoned, clarified the situation, and his mother removed the neg his son left. With a delayed-confirmation process, this particular negative could have been averted altogether.
It's just a thought...