There are many flaws an pitfalls with the feedback forum.
There are however things you can such as replying to feedback left for you especially if its negative.

I don't agree with being able to leave only 1 feedback comment.
As it stands you can leave ONLY 1 feedback comment per transaction. If I have several transactions with the same person, I want to have the option to comment on each. 1 good experience or for that matter 1 bad experience does not constitute a pattern. Sometimes you might jump the gun by posting negative feedback for something like not receiving merchandise when in fact it might be the fault of the Post Office . Once posted you might have blemished someones record unfairly.

As far as the positive feedback numbers, there are two. When you go to the feedback forum , there is a listing of total comments pro neutral or negative but the number next to the star indicates how many different trading partners you have had. I would pay heed to that number as well.

I do however agree that witholding feedback to protect one's feedback record works against everyone.
Perhaps the seller should have to post his feedback upon receipt of payment.
As it stands now many sellers reserve the right to post feedback until they see what you have to say.

Its amazing that for most part a purchasers feedback record counts for nothing. In the majority of cases you are always asked to remit funds before the seller ships you his product. Why doesn't trust work both ways? What is an unblemished feedback record of several hundred positives worth when the E-mail says If you are sending a personal check allow 7 days for it to clear.