I too am mostly a buyer. I think I've only sold about 10 items on eBay; flash cards and amateur radio gear. So I agree that the only thing that a seller can leave as feedback is how well (or not) the buyer communicates and pays for the item. For my sales, I left feedback before shipping the product. Like
Phazer, I rarely encounter this with my own purchases. Withholding feedback as a seller until the buyer leaves his/hers is one of the things that I read in the "eBay Hacks" book, but that I did not agree with. Also, I do not have separate buyer and seller eBay IDs. My understanding is that most high-level eBayers engage in this type of separation, as
chiral has pointed out one reason why this is done ("a negative hurts a seller far more than it hurts a buyer"). My personal feeling about this is that you can't get a clear picture of your trading partner unless you see how they operate on
both sides of a transaction.
Communication is high on the list with me. If I have a problem with an item, the seller is contacted and given plenty of time to respond. Most of the time things are settled very quickly and to the satisfaction of both sides. The two times I really wanted to leave a negative, eBay canceled the seller's account before I could. A recent transaction which resulted in a neutral was played out for well over a month. A camera I bought for work was never delivered:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0167299554 (JE3462HR Chromachip camera for $30)
My neutral feedback: "LostGR8DealPaid11/1EMail&Phoned7xIn40DaysToldWouldShip11/30Refunded12/14&NoStory"
(I like using all 80 characters in my feedback

). Interestingly enough, this seller
did leave feedback right after I paid for the camera. In my mind, he did not deserve a negative since I was refunded but the lack of communication needed to be noted.
If eBay makes changes to the feedback system where comments like this cannot be left, then it's a step backwards for buyers.