Many on eBay are a Seller and also a Buyer. Give both sides an equal and unbiased importance.
Let the Sellers have ability to leave negative/neutral feedback along with Star selection for the purchase a buyer made.
Stars: Communication (responsive), cooperation (in resolve any issues), Acknowledgment (timely item receipt), Payment (how much time he took to pay after checkout), Recommend (recommend this buyer to have as buyer).
Also, if a buyer receives few negatives/neutrals, let that account as buyer be restricted.
Also, introduction of Power Buyer.
We know that its difficult to digest yourself and for your programming/development team. One needs to go with the future and update things along with the Changing World.
Regards