For starters, eBay has never been very aggressive or particularly interested in disciplining buyers who violate its policies, so the new reporting hub and the negative-feedback removal of bad buyers will have little effect unless eBay pumps up its enforcement, Garriss said. "Supposedly, eBay has always been policing buyer behavior, but it never happened quite right," he said. "Many sellers will confirm that buyers have tended to not be held to the rules."

Garriss, also CEO of Gotham City Online, an apparel store on eBay is also concerned about what he calls a lack of transparency in the detailed ratings that buyers can leave for sellers. As it stands now, sellers get aggregate results every month for these so-called DSRs (detailed seller ratings), and don't know how individual buyers rated them.

This lack of transparency lends itself to buyer retaliation, and more so since eBay this year started tying DSRs to sellers' visibility on search engine results and to fee discounts, Garriss said. Now that sellers can only leave positive ratings for buyers, eBay should tie specific DSR evaluations to individual buyers, thus giving sellers a chance to, if necessary, defend themselves from unfair actions, he said. DSRs let buyers rate sellers specifically in four areas with a scale of one to five stars: accuracy of item description, communication, shipping time, and shipping and handling charges.

Nonetheless, Garriss said that PESA has been encouraged by eBay's willingness to listen to sellers' concerns, and by the company's pledge that the changes in feedback and other areas are open to revision.

Brian Burke, eBay's director of global feedback policy, said that there will always be sellers who are intensely opposed to the feedback changes and buyers who will try to abuse the system, but eBay is convinced that ultimately everyone will benefit.

"Most of the sellers understood why were doing what we were doing even back in January when we made the announcement," Burke said.

"There will still be sellers upset about the changes, and some buyers will try to abuse it. Hopefully, the reporting structures we've put in place and the policy changes will provide sellers with the protections they need, and we'll correct things as needed on that front," he said.

This is the global rollout schedule for the feedback changes:

May 12: Australia

May 15: U.K., Ireland

May 19: US, Canada

May 20: France, Spain, Italy, Netherlands, Poland, Belgium

May 21: Hong Kong, Singapore, India, Malaysia, Philippines

May 22: Germany, Austria, Switzerland

Some changes will be implemented the week of May 27 worldwide.