It sounds ok in theory, but aside from what I suspect would be a lot of buyers baulking at the thought of being judged, I think the overall ratings would be skewed by a lot of sellers who couldn't be bothered filling out individual ratings for every buyer they get, unless they want to mark them low (possibly mitigated by a bulk 5-star leaving tool, but still an additional chore).
If anything at all, I would prefer to see some cold, hard facts and stats, which are super-easy to generate, with the added benefit of being objective - # purchases, # completed transactions (if those two are at odds, you'd know you're dealing with someone who doesn't always pay, and it's easy enough to allow a few for circumstances beyond a buyer's control etc, then maybe #refunds / returns. That last one might be a bit controversial, for many it would (understandably) feel like private info, but I would be happy for seller FB to go as well and have similar stats displayed. # items sold / completed transactions, #refund / return requests for INR or INAD.
