It is such a shame that a small group of sellers make them reassess their rules. As a seller, I value the ability to leave a neg if I get stung by a poor payer (I think in 3 yrs I have left 2 negs - both for non payment and no corro and both of those negs are no longer ebay members), and I value being able to see my buyers other feedback from sellers. In saying that though, I am very diligent with communication, and postage, and have never received a negative. Customer service is very important to me, coming from a past retail background.
But you are right, there are sellers i have bought from that I found quite hard to deal with due to lack of communication.
ETA - agree on the fees... basic listing should be free, pay for extras. Final valuation fee is sufficient.