I've been buying and selling on eBay for years, I even did their £90 eBay "University" course (waste of time and money) and I also think the new feedback system is pants. I've had a couple of bad experiences with buyers leaving bad feedback, one even got VERY abusive in emails (personally and racially) - it's all very well eBay saying report them, copy in their emails etc, but you never get to find out what eBay actually do about it (if they do anything at all.) I even had one seller cashed a cheque for £40 said he hadn't, I got the bank to prove he had cashed it, reported it, etc...he was even making abusive phone calls in the middle of the night to me, sometimes 10 times in one night, but all I was told by eBay was to report him to the police. I did, but they referred me back to eBay and said it was their problem. So I took it into my own hands, did some detective work through the feedback system, and found a lot of his customers had been having the same experience as me. After a lot of messaging and phoning each other, we managed to track him down, I even found out the phone number he was ringing us all from at night was a call centre he worked at, so I gave all the info to the police and they dealt with it. Incidentally, the police were disgusted with eBay.
How about us all boycotting the new feedback system and not leaving any? Would it work? Would need an awful lot of people to do it, though!