I also don't blame Ebay for these problems.
The problem I would have is that you're then letting somebody at Ebay - hardly an expert - make decisions about signatures, or anything else like that.
Do you want to be a customer who informs yourself and can have faith in your own decisions....
OR
Do you want a company without any real knowledge to make those decisions for you? Or rather, decide what auctions are available and which aren't?
Personally, I'd let the buyer be the one to decide. Paypal allows for refunds, etc., so you can always get your money back within a window - so there IS recourse.