Seller negative feedback removal was a good thing as it prevented slanging matches across accounts, especially when it is the seller who is supposed to offer A1 customer service. A seller can still comment on negative comments and have them removed if Ebay agree to it.
Actually the law changed well before Ebay existed, it just wasn't implemented by Ebay as they left any problems for the buyer/seller to sort out between themselves. This changed after pressure from the EU.