@first i didn't like the option of not being able to rate buyers but hey, sometimes i forget to leave them feedback so isn't this the same ? usually the only ones i want to give negative feedback are newbies therefore if buyer has many positive feedback, say 20 or + chances are he's a good legit deal hunter (buyer) if newbie with 0 or 1 score well... he's a newbie, can't expect much, worse case he gives you neutral or negative then you complain to ebay
you get your closing fees back for npb and life goes on
momoftwingles2 is totally right. as a buyer that i also am, i like to give feedback accordingly to the product i receive ie if shipping took forever, if seller never replied to me or if item was not as described (keep in mind lots of sellers are not powersellers but newbies just getting rid of junk)
as a seller well, let it be just make sure you're fair and hopefully won't get any pissed off customers 🙂