What they really need to do (just IMHO 🙂 ) is make it a clear-cut good / bad system. As far as I'm concerned, if a buyer's problem isn't bad enough to leave an outright neg and/or open a case about it, it's not bad enough to get the seller restricted or banned from selling, so shouldn't have that potential.

Secondly, if they do want to count every last little niggling issue against sellers (and restrict them from selling) when said issues can be relegated to minor irks, many of which are not only absolutely no fault of the seller but are typically inherent to online shopping, or the buyer themselves, no matter which site the buyer may have bought from (eg delivery time, not paying attention to details or description - people like that shouldn't even be rating item description, let alone given the opportunity to kick a seller off eBay due to their poor attention skills but fabulous imagination skills), then eBay should recognise all the sellers that remain are "premium" - you have to be to hang in there in this kind of environment (seemingly protected sellers notwithstanding), and the sellers who are ticking certain service boxes are no more or less "premium" than the ones who aren't.